EP4137235A1 - Coating device - Google Patents

Abstract

A coating device (1) for superficially applying a coating agent to a workpiece (4) is proposed. The coating device (1) comprises a machine frame (2) with a workpiece holder (3), a coating medium source (8, 9) and a compressed air source (5). The coating device (1) also comprises a rotary unit (12) that can be rotated relative to the machine frame (2) and has a pump (17) and a plurality of spray units (20), the pump (17) being connected on the suction side via a fluid-conducting swivel joint (13) to the Coating agent source (8.9) and the pressure side is connected to the spray units (20). It is essential that the rotation unit (12) has a pneumatic valve device (18), and that the spray units (20) each have a compressed air-controlled valve (21) for controlling the dispensing of coating agent, the valve device (18) on the air inlet side via a fluid-conducting rotary feedthrough (14), preferably a single-channel rotary feedthrough, is connected to the compressed air source (5) and to the compressed air-controlled valves (21) of the spray units (20) on the exhaust air side.

Description

The invention relates to a coating device according to the preamble of claim 1.

Such coating devices are known from the prior art and are used for superficially applying a coating agent to a workpiece. The coating agent can be, for example, a paint, in particular a clear paint or pigmented paint, stain or paint. The workpiece is, for example, a wood material part or an assembly of such parts for the production of furniture. For coating, the workpiece is arranged on a workpiece holder and then provided with the coating agent by means of a plurality of moving spray units.

In order to achieve high productivity, it has proven itself in the prior art to design coating devices each with a machine frame and a rotary unit that can be rotated relative to the machine frame. The machine frame includes the workpiece holder already mentioned above, while the rotation unit includes the plurality of spray units, which have also already been mentioned. When the rotation unit rotates relative to the machine frame, the spray units sweep over the workpiece and thereby distribute the coating agent onto the workpiece surface.

A design challenge that must be overcome in known coating devices is coating agent from a fixed source of coating agent for the moving rotation unit and the provide spray units arranged thereon. Swivel joints are usually used for this purpose, each of which has a fixed and a rotatable swivel joint part.

The stationary swivel joint part is arranged on the machine frame, while the rotatable swivel joint part is arranged on the rotation unit. The pivot joint parts mentioned are connected to one another in a sealing manner, forming a coating medium channel. At the same time, the pivot parts can be rotated relative to one another, with the fluid-conducting coating agent channel remaining independent of the relative angle of rotation between the pivot parts. The stationary swivel joint part includes an inlet-side connection for the coating agent channel, to which the coating agent source is connected. The rotatable swivel joint part includes a connection for providing the coating agent for the spray units on the rotary unit.

From the U.S. 2006/0060677 A1 it is known to arrange a pump on the rotary unit. The pump is connected to the coating agent source on the suction side via the rotary joint and to the spray units on the pressure side. In comparison to an arrangement in which the pump is not arranged on the rotary unit but on the machine frame, the arrangement according to FIG U.S. 2006/0060677 A1 to increase the service life of the swivel joint used in each case. This is due to the fact that the coating agent is not fed through the swivel joint under high pressure. Instead, the coating material is pressurized downstream to the swivel and then by the pump and delivered to the spray units. This protects the seals of the swivel joint in particular. This leads to a longer tightness of the swivel joint.

Due to the ever-increasing variety of workpieces to be coated, in particular furniture parts, it is desirable to be able to easily change the mode of operation of the coating device if necessary. Which also includes For example, an individually adaptable configuration of the coating agent output depending on the individual dimensions or the material used for the workpieces to be coated.

However, one disadvantage of known coating devices is that they are usually designed as special constructions, which are primarily used for coating work pieces that are similar to one another. It is possible to adapt the design parameters of the coating device, such as the number of spray units and their movement path and speed, to changing conditions of use. However, the required design effort is too high to be able to react in an economically efficient manner to the large number of variants of the workpieces to be coated.

In particular, a high level of design effort is required if actively controllable components, for example control elements for dispensing the coating agent, are to be retrofitted. Because an increasing number of such components usually requires a correspondingly high number of control lines, which have to be routed from the machine frame to the rotary unit in a complex manner. If the components to be controlled require an energy supply for their operation, additional energy lines must also be routed from the machine frame to the rotary unit in a structurally complex manner. This makes the coating device technically complex and therefore also expensive.

The object on which the invention is based is to provide a coating device which is associated with a high degree of adaptability to changing conditions of use, good controllability and at the same time a simple structure.

The object is achieved by a coating device according to claim 1. Advantageous developments can be found in the dependent subclaims. These subclaims contain combinations of features that are also independent from the characterizing part of claim 1 and without its features can be independent inventions, possibly in combination with features of other subclaims.

The coating device according to the invention comprises a machine frame with a workpiece holder, a source of coating agent and a source of compressed air. The coating device also includes a rotary unit that can be rotated relative to the machine frame and has a pump and a plurality of spray units, the pump being connected to the coating agent source on the suction side via a fluid-conducting rotary joint and to the spray units on the pressure side.

According to the invention, the rotation unit has a pneumatic valve device. Furthermore, the spray units each have a compressed air-controlled valve for controlling the dispensing of coating agent. The valve device is connected on the supply air side at least via a fluid-conducting rotary feedthrough to the compressed air source and on the exhaust air side to the compressed air-controlled valves of the spray units.

The invention is based on the knowledge that the arrangement of an additional component in the form of the pneumatic valve device on the rotary unit leads to an overall simple construction of the coating device and at the same time improves its controllability.

The simple structure of the coating device results from the fact that a rotary feedthrough known per se can be used to provide compressed air for the pneumatic components of the rotary unit. In this case, the rotary leadthrough preferably has only one compressed air duct, which allows a pneumatic connection between the compressed air source of the machine frame and the rotary unit that is independent of the angle of rotation. For this purpose, the rotary feedthrough can have an overall simple, robust and structurally compact design: a fixed part of the rotary feedthrough is arranged on the machine frame and is fluid-conducting via an inlet connection connected to the compressed air source. A movable part of the rotary feedthrough is arranged on the rotary unit and is connected to the stationary part of the rotary feedthrough in a sealing and relatively rotatable manner, forming a fluid path. The fluid path between the two parts of the rotating union remains independent of a rotation angle between the stationary and the moving part of the rotating union. The fluid path opens into an exhaust air connection of the movable part, which is connected to the valve device.

By means of the valve device, the compressed air flow provided via the rotary feedthrough can be distributed to a large number of pneumatically controlled and/or pneumatically operated components, which can be arranged on the rotary unit in large numbers as required. The arrangement of the valve device on the rotation unit favors the simple design of the rotary feedthrough. Preferably, as already explained above, the compressed air can be routed from the compressed air source to the rotary unit via only one compressed air duct and distributed to a large number of compressed air lines on the exhaust air side by means of the valve device. Said compressed air lines lead to the valves of the spray units and can be made comparatively short due to the arrangement of the valve device on the rotation unit. This improves the controllability of the valves.

It is within the scope of the invention that the compressed air flow between the rotary feedthrough and the valve device can be divided into several partial flows in order to be able to supply further pneumatic components on the rotary unit with compressed air independently of the valve device. It is also within the scope of the invention that further pneumatic components can be arranged in the pneumatic connection between the compressed air source and the valve device in addition to the rotary feedthrough.

The valve device is preferably designed as a valve island. Such a valve terminal can be equipped in a flexible manner and as required with a large number of so-called valve disks, which are adapted to the type and number can be adapted to the driven and / or to be controlled pneumatic components of the rotary unit. For this purpose, the valve terminal usually has a distributor strip with a central supply air connection. The distributor rail also has a large number of distributor connections, via which the valve disks are supplied with compressed air. As a result, the compressed air for the valves to be controlled can be provided in a structurally compact manner.

In an advantageous development, the pump for the coating agent is designed to be operated by compressed air and is connected to the compressed air source at least via the rotary feedthrough.

According to the development described above, the compressed air is used both to control the dispensing of coating agent and to drive the pump. It is therefore an advantage that the use of different types of energy and signal transmission can be dispensed with and compressed air is used both for control and as an energy carrier.

It is within the scope of the advantageous further development that the compressed air operated pump is connected to the rotary leadthrough via the pneumatic valve device and can preferably be controlled by means of the valve device. However, the pump is preferably operated independently of the pneumatic valve device and is connected to the rotary feedthrough via a pneumatic branching element, which can be designed, for example, as a T-piece or Y-piece. The pneumatic branching element can easily be arranged in a compressed air line between the rotary feedthrough and the valve device. As a result, a compressed air flow can be routed via the rotary feedthrough to the rotation unit and divided between the valve device and the pump by means of the pneumatic branching element. This has the advantage, among other things, that the compressed air flow required for the pump is not limited by the valve device. Furthermore, the valve device can be of compact design, since its air-guiding areas and their cross sections do not have to be dimensioned depending on a required compressed air flow for the operation of the pump.

In an advantageous development, the machine frame includes an electrical control unit and the pneumatic valve device is designed to be electrically controllable. Furthermore, the rotary leadthrough has at least one signal line. The control unit and at least the valve device are connected to one another in terms of signal technology via this signal line of the rotary leadthrough.

According to the development described above, the rotary feedthrough is not only designed to conduct fluids, but also to transmit signals. Such an embodiment does not stand in contrast to a simple construction of the rotary leadthrough which is simple according to the invention. Rather, the signal line for transmitting electrical signals can be designed in a simple manner in the form of an electrical sliding contact between the fixed and the moving part of the rotary feedthrough. It is within the scope of the advantageous development that the signal line has multiple poles and that a number of sliding contacts are accordingly formed in the rotary feedthrough. Furthermore, it is within the scope of the advantageous development that the signal line is designed as an optical signal line for the transmission of optical signals. For this purpose, the parts of the rotary feedthrough that can be rotated in opposite directions are connected to one another via optical coupling elements. The electrical control unit and the valve device preferably each have at least one optoelectronic element, by means of which electrical signals can be converted into optical signals and vice versa.

The control unit can be embodied as a control computer or as a programmable logic controller, each of which is operated independently or in a control network with other control units. A control program is preferably implemented on the control unit, which represents the control logic with which at least the valve device and thus the valves of the spray units can be controlled. If the pump is supplied with compressed air via the valve device, the pump can preferably also be controlled via the valve device.

In a simple embodiment, the control unit is used to output control signals in the form of control voltages, preferably in the range of 0-24 volts. These voltages can be provided directly to the valves of the valve device via the control line of the rotary feedthrough in order to control them. After the voltage has dropped, said valves can be brought into an unactuated basic position, for example by means of a spring return. Basically, apart from the electrical control signals, no electrical power supply is required for the operation of the valve device.

The valve device can have at least one analog and/or digital signal input. This signal input is used to receive control signals from the control unit, by means of which the compressed air distribution on the rotary unit can be controlled. A plurality of signal inputs can be combined spatially and configured as a multi-pole connection, the poles of which are each connected to a valve of the valve device in order to control it directly. In particular, this is conceivable if the valve device is designed as a valve island.

The coating device preferably has a workpiece detection unit which is designed to detect the presence and preferably also the dimensions of the workpiece to be coated and, depending thereon, to output a control signal to the control unit. The control unit evaluates the control signal and emits one or more opening signals to the valve device in order to preferably only open the valves of those spray units that are located above the workpiece. In this way, coating agent can only be dispensed in the area of the workpiece to be coated and thus with a high degree of efficiency.

It is also within the scope of the advantageous development that a rotation angle sensor is designed to detect the rotation position of the rotation unit relative to the machine frame and a measured rotation angle to be sent to the control unit. The control unit preferably stores the positions at which the spray units are located on the rotation unit. Thus, depending on the detected rotation angle, it can be determined which of the spray units is located in the area above a workpiece to be coated. In this case, it is not absolutely necessary for the coating device to have a workpiece detection unit, by means of which the presence or the dimensions of the workpiece to be coated are detected. Instead, the coating agent can always be dispensed when one or more of the spray units sweep over a defined area of the workpiece holder. Coating agent can thus be dispensed independently of whether or not there is a workpiece to be coated in this swept area. Such an arrangement is particularly advantageous when the workpieces to be coated are placed in the coating device in large numbers and at short distances from one another.

It is within the scope of the advantageous development that at least one other component that is located on the rotation unit is also controlled via the control line of the rotary feedthrough. In a simple manner, the rotary leadthrough can output the appropriate control signals via the control line to the valve device, which forwards the signals to the other components to be controlled. However, it is also within the scope of the advantageous development that the valve device is not located in the signal path between the rotary feedthrough and the other components to be controlled. Bus communication can be provided in a simple manner, so that the signal path between the rotary feedthrough and the valve device can be divided in order to be able to control the other components to be controlled with little wiring effort and preferably only one signal line of the rotary feedthrough.

In an advantageous development, the rotary feedthrough is designed for electrical energy transmission. Furthermore, this includes the machine frame an electrical voltage source which is connected in terms of energy at least to the valve device via the rotary feedthrough.

The valve device is preferably equipped with components which require a permanent power supply, for example a microcontroller or another data-processing unit. In addition, it is possible to provide at least one analog/digital converter or a sensor on the valve device. In addition, the valve device can be designed in such a way that communication with the control unit can take place using standardized protocols such as TCP-IP and in real time. So that electrical energy can be provided by the electrical voltage source for the valve device and preferably other components on the rotary unit, the rotary leadthrough preferably has an electrical power line for electrical energy transmission in addition to the signal line. The electrical power line is preferably designed as a two-pole sliding contact. The power line is connected on the one hand to the electrical voltage source and on the other hand to the valve device. In addition or as an alternative, wireless energy transmission by means of the rotary feedthrough is also conceivable. In this case, the electrical energy can be transmitted through non-wired electromagnetic fields, in particular by means of inductive and/or capacitive coupling, instead of along a power line and by means of electrical contacts.
In another advantageous development, at least the electrically controllable valve device and the control unit are connected to one another in terms of signals by means of a wireless transmitter-receiver arrangement.

As a result of the development described above, control signals can be transmitted wirelessly from the control unit to the valve device and independently of the rotary feedthrough. The transmitter-receiver arrangement here comprises at least a first communication element, which is connected to the control unit, and a second communication element, which is connected to the valve device, with the two communication elements being used for the wireless transmission of control signals. The second communication element can preferably also be electrically connected to another be controllable component on the rotation unit connected in terms of signaling.

It is within the scope of the advantageous development that the first communication element is a radio transmitter and the second communication element is a radio receiver in order to be able to communicate control signals wirelessly from the control unit to the valve device. Alternatively, the first and the second communication element can each be designed as a WiFi or WLAN module whose signaling communication takes place via a common network in which they are operated. The first communication element can be connected to the voltage source on the machine frame for power supply. The second communication element arranged on the rotary unit can have its own energy store, e.g. in the form of an electric battery.

In an advantageous development, a pneumatically operated electrical generator is arranged on the rotation unit, which is connected to the compressed air source at least via the rotary feedthrough and is designed to supply at least the valve device with electrical energy.

According to the development described above, the rotary feedthrough serves to provide a compressed air flow for the compressed air-operated generator. This converts this compressed air flow into electrical energy. This makes it possible to design the rotary feedthrough without the possibility of transmitting electrical energy and to operate the electrically operated components of the rotary unit, preferably independently of a stationary voltage source on the machine frame. In order to ensure an uninterrupted supply of electrical energy to the rotary unit, an electrical accumulator can serve as an electrical intermediate store. The battery can preferably be charged by means of the generator. If necessary, other components on the rotary unit that require an electrical energy supply can also be supplied with electrical energy by means of the generator and/or the rechargeable battery.

In an advantageous further development, the pump is connected to the rotary feedthrough at least via a pump pressure regulator on the supply air side. The pump pressure regulator is preferably designed to be electrically controllable.

The purpose of the pump pressure regulator is to regulate a possibly fluctuating inlet pressure of the compressed air provided through the rotary feedthrough to a constant and usually lower outlet pressure. The pump pressure regulator preferably includes a so-called pressure booster in order to regulate the inlet pressure to a higher outlet pressure.

Since the delivery of coating agent from the spray units is directly dependent on the pump pressure, the quality of the coating result can also be optimized by such a regulated drive pressure of the pump.

The pump pressure regulator can be designed in a simple manner as a mechanical component, with the outlet pressure to be regulated being able to be set manually and directly on the pump pressure regulator in a manner known per se. The pump pressure regulator is preferably designed as an electrically controllable component. In this case, the control unit is designed to output a control signal for regulating the outlet pressure. If the rotary feedthrough has a signal line, the control signal can be output from the control unit to the pump pressure regulator via the rotary feedthrough. Here, the valve device can be in the signal path between the pump pressure regulator and the rotary union. If the coating device has a wireless transmitter-receiver arrangement, this can be used to transmit the control signal from the control unit to the pump pressure regulator. It is also within the scope of the advantageous development that the pump pressure regulator can be controlled pneumatically and is preferably controlled via the valve device.

The control unit is preferably connected to an easy-to-use input element, e.g. a tablet or the control panel of the coating device. As a result, the outlet pressure to be regulated can be specified in a simple manner.

If the pump is connected to the rotary feedthrough via the valve device in order to be supplied with compressed air, the pump pressure regulator can advantageously be integrated into the valve device on the exhaust air side. In this case, the control signal from the control unit can be given to the valve device, which outputs the control signal directly or in processed form to the pump pressure regulator. In particular, the valve device can include an analog-to-digital converter in order to convert the control signal for the pump pressure regulator.

If the pump is connected to the rotary union via the pneumatic branching element in order to be able to be operated independently of the valve device, the pump pressure regulator is preferably arranged between said branching element and the pump. In this arrangement, the pump pressure regulator preferably also serves to control pump operation. For this purpose, an output pressure to be set can be transmitted to the pump pressure regulator as required by means of a corresponding control signal. For example, the specified outlet pressure corresponds to 0 bar if pump operation is to be ended. Accordingly, the outlet pressure to be set can correspond to 4 bar, for example, in order to start pump operation. In this embodiment, the compressed air supply to the pump and the pump pressure regulator is independent of the valve device. Nevertheless, the valve device can be in the signal path between the control device and the pump pressure regulator and also emit signals to electrically controllable components of the rotary unit which are not pneumatically connected to the valve device.

It is also within the scope of the advantageous development that the pump pressure regulator can include a measuring element, which is used to measure the regulated pump pressure and to output it to the control unit. This allows the operation of the pump to be monitored during the coating process.

Any electrical voltage that may be required to operate the electrically controllable pump pressure regulator can be provided in a simple manner via the rotary feedthrough or via the compressed air-operated generator on the rotary unit. The valve device can preferably also be used to provide electrical energy for the pump pressure regulator or other electrical components located on the rotation unit.

In an advantageous further development, a coating medium pressure regulator is arranged between the pump and at least one of the spray units, the coating medium pressure regulator preferably being designed to be electrically controllable.

The purpose of the coating agent pressure regulator is to regulate the pressure of the coating agent in relation to the delivery pressure of the pump to an adjustable outlet pressure and to reduce the applied delivery pressure as required or to increase it using a pressure booster. The coating agent pressure regulator can easily be designed as a mechanical component in which the outlet pressure can be set manually. Alternatively, the coating medium pressure regulator can be pneumatically controlled. If the coating agent pressure regulator is designed to be electrically controllable, control signals can be output from the control unit to the coating agent pressure regulator via the signal line of the rotary feedthrough or via the wireless transmitter-receiver arrangement. It is within the scope of the advantageous development that the valve device is located in the signal path between the control unit and the coating agent pressure regulator. An electrical voltage that may be required to operate the electrically controllable coating agent pressure regulator can be provided analogously to the statements regarding the pump pressure regulator via the rotary union or via the compressed air-operated generator.

In an advantageous development, the spray units each have a compressed air-operated atomizer unit for atomizing the coating agent, the atomizer unit being connected to the compressed air source at least via the rotary feedthrough.

The atomizer unit is used to convert the dispensed coating agent into a large number of finely distributed droplets using compressed air. This allows the coating agent to be distributed homogeneously on the workpiece surface and the coating quality to be optimized. For this purpose, the atomizer unit can be operatively connected to the spray unit in different ways. It is within the scope of the advantageous development that the atomizer unit has at least one compressed air outlet, which is arranged behind a coating agent dispensing opening of the spray unit with respect to the direction of flow of the coating agent. The compressed air outlet is preferably designed as an annular gap. Additionally or alternatively, the compressed air outlet can be designed as one or more bores, which are located laterally behind the coating agent dispensing opening of the spray unit. It is also within the scope of the advantageous development that the atomizer unit and the spray unit are structurally combined and arranged in a common housing or are structurally separate from one another.

It is within the scope of the advantageous development that the atomizer unit is pneumatically connected via the valve device with the rotary feedthrough. In this case, the operation of the atomizer unit can be controlled by means of the valve device. Alternatively, the atomizer unit is connected to the rotary feedthrough via the pneumatic branching element already described above or another branching element and is operated independently of the pneumatic valve device. The pneumatic branching element can be used for this be designed in the manner already described as a T-piece or as a comparable pneumatic component in order to divide the compressed air flow, which is provided by means of the rotary feedthrough for the rotation unit, at least between the valve device and the atomizer unit.

In an advantageous development, an atomizer pressure regulator is arranged between at least one of the atomizer units and the rotary feedthrough. The atomizer pressure regulator is preferably designed to be electrically controllable.

By means of the atomizer pressure regulator, it is possible, analogously to the explanations regarding the pump pressure regulator, to regulate an inlet pressure present at the atomizer pressure regulator to an adjustable outlet pressure. The inlet pressure can preferably be reduced or increased by means of a pressure booster. Investigations by the applicant have shown that an outlet pressure of between 2 and 4 bar should preferably be set for the atomizer pressure regulator in order to achieve an optimum coating result.

The atomizer pressure regulator is preferably connected to a plurality of atomizer units, preferably to all atomizer units of the rotary unit. The advantage here is that only one atomizer pressure regulator is required to regulate the atomizer pressures of a number of atomizer units. If the atomizer pressure regulator is connected to a plurality of atomizer units, an arrangement of a plurality of pneumatic branching elements can be arranged between the atomizer pressure regulator and the atomizer units. As a result, the compressed air flow output by the atomizer pressure regulator can be divided among the plurality of atomizer units, preferably among all atomizer units. It is within the scope of the advantageous development that the atomizer pressure regulator can be controlled mechanically or pneumatically.

The atomizer pressure regulator is preferably designed to be electrically controllable. In this case, the control unit is signaled via the signal line of the rotary union or connected to the nebulizer pressure regulator via the wireless transceiver assembly. In this case, the required outlet pressure for an optimal coating result can be set by means of a control signal from the control unit. It is also within the scope of the advantageous development that the atomizer pressure regulator can include a sensor for measuring and monitoring the atomization pressure and communicates the outlet pressure to the control unit during operation of the coating device. It is within the scope of the advantageous development that the valve device is located in the signal path between the rotary feedthrough and the atomizer pressure regulator.

Any electrical energy required to operate the electrically controllable atomizer pressure regulator can be provided in a simple manner via the rotary leadthrough. Electrical energy for the atomizer pressure regulator can preferably also be provided via the valve device if this is connected in terms of energy to the rotary feedthrough. Alternatively, the electrical energy that may be required can be provided via the compressed air-driven generator.

In an advantageous development, at least one of the spray units has at least one compressed-air-operated shaping air unit for setting a jet shape of the coating medium dispensed from the spraying unit, the shaping air unit being connected to the compressed air source at least via the rotary feedthrough.

The jet shape of the coating agent discharged from the spray unit represents an important influencing factor for the achievable coating quality. The shaping air unit serves to influence said jet form of the coating agent. For this purpose, the shaping air unit has a mechanically adjustable air cap on which one or more air nozzles are located. By mechanical adjustment of the air cap, the compressed air flow can be changed as required in order to adjust the jet shape of the coating agent depending on this.

It is within the scope of the advantageous further development that the rotary feedthrough is pneumatically connected to the shaping air unit via the valve device. Alternatively, the shaping air unit is preferably connected to the rotary feedthrough via the pneumatic branching element already mentioned above or another pneumatic branching element. In this case, the shaping air unit is supplied with compressed air independently of the pneumatic valve device. In the manner already explained, the pneumatic branching element can comprise a T-piece or a comparable pneumatic component in order to divide the compressed air flow, which is provided for the rotary unit by means of the rotary feedthrough, at least between the valve device and the shaping air unit.

In an advantageous development, a shaping air pressure regulator is arranged between the shaping air unit and the rotary feedthrough, which is preferably designed to be electrically controllable.

By means of the shaping air pressure regulator, the shaping air pressure can be regulated from an increased inlet pressure to an adjustable outlet pressure and, if necessary, reduced or increased. The pressure level of the shaping air pressure is preferably between 2 and 4 bar, so that the outlet pressure of the shaping air pressure regulator can be adjusted accordingly in order to achieve an optimal coating result. The output pressure of the shaping air pressure regulator can be controlled manually or pneumatically, analogously to the statements made with regard to the pressure regulators already described.

The shaping air pressure regulator is preferably designed to be electrically controllable. In this case, the control unit is connected to the shaping air pressure regulator via the signal line of the rotary union or by means of the wireless transmitter-receiver unit. As a result, the required outlet pressure for an optimal coating result can be set by means of a control signal from the control unit. It is within the advantageous development that the Form air pressure regulator may include a sensor for measuring and monitoring the form air pressure and communicates the output pressure during operation of the coating device to the control unit. It is within the scope of the advantageous development that the valve device is located in the signal path between the rotary leadthrough and the shaping air pressure regulator.

Depending on whether the shaping air unit is connected to the rotary union via the valve device or via the branching element, the shaping air pressure regulator can be arranged between the shaping air unit and the valve device or between the shaping air unit and the branching element. The shaping air pressure regulator is preferably connected to a plurality of shaping air units, preferably to all shaping air units, on the rotary unit. The advantage here is that only one shaping air pressure regulator is required to control the shaping air pressures of several shaping air units.

Any electrical energy required to operate the electrically controllable shaping air pressure regulator can be provided in a simple manner via the rotary feedthrough. Electrical energy for the shaping air pressure regulator can preferably also be provided via the valve device if this is connected in terms of energy to the rotary leadthrough. Alternatively, the electrical energy that may be required can be provided via the compressed air-driven generator.

In an advantageous development, the rotation unit comprises a plurality of adjusting means, on each of which at least one of the spray units is arranged. The adjusting means are designed to set a position, preferably an orientation, of the at least one spray unit arranged on them relative to the workpiece holder.

According to the development described above, the adjustment means are used to set the position and preferably the orientation of the spray units relative to the workpiece in such a way that it can be coated evenly. This is advantageous because the positions of the spray units, which each have a Include position and orientation, change relative to the workpiece holder and the workpiece arranged thereon due to the rotational movement of the rotary unit. The adjusting means is preferably used only for orientation, that is to say setting the relative angular position of at least one spray unit with respect to the workpiece.

The adjusting means are preferably designed to be controlled as a function of a rotational position of the rotary unit relative to the machine frame. A mechanical control is particularly conceivable here. For this purpose, the adjusting means can be coupled to a cam track, which is arranged on the machine frame, for example by means of a rod or any other force transmission element. The cam track is preferably formed by a groove or edge running around the axis of rotation of the rotation unit. The course of the curved path preferably corresponds approximately to an oval or preferably to a Cassini curve, the shape of which essentially corresponds to that of an oval indented on two sides. When the rotary unit rotates, the end of the rod slides along the cam track and exerts forces on the adjusting means in accordance with the course of the cam track. These forces in turn bring about an adjustment of the spray unit connected to the actuating means.

In an advantageous development, the adjusting means includes an electric drive and is designed to be electrically controllable.

The development described above makes it possible to electrically adjust the spray unit or several spray units connected to the adjusting means. The adjusting means are preferably each a servo drive, with which the position, in particular the orientation of the spray unit can be adjusted in a path-controlled and/or angle-controlled manner. The electrical drive of the actuating means is preferably connected to the control unit via the rotary feedthrough in terms of signals, with the electrically controllable valve device preferably being located in the signal path between the rotary feedthrough and the actuating means. Alternatively, the actuating means is via the wireless transceiver arrangement connected to the control unit in terms of signals. The electrical energy required for the electrical drive can preferably be provided via the rotary feedthrough and preferably via the valve device. Alternatively, the required electrical energy can be provided via the compressed air-driven generator.

The advantage of an electrically controlled adjustment of the spray unit is that it can be flexibly adjusted and is not prone to malfunctions during operation. In particular, it is easily possible to adapt the orientation of the spray units to workpieces with different geometries and dimensions.

In an advantageous development, the workpiece holder is designed as a conveyor belt in order to convey the workpiece by means of a linear movement from an entry area of the machine frame to an exit area. In this case, one of the spray units sweeps over the workpiece in the inlet area and in the outlet area during a rotary movement of the rotation unit. The workpiece is preferably swept over along at least two intersecting movement paths, so that an intersecting spray pattern results on the workpiece.

According to the development described above, the workpiece is arranged on the conveyor belt in front of the inlet area and is conveyed by means of the conveyor belt into the outlet area and beyond it. The conveying movement preferably takes place at an adjustable and preferably constant speed.

In the entry area, the workpiece is swept over by at least one spray unit of the rotation unit. The superimposed rotational movement of the rotation unit and the linear displacement movement of the workpiece results in a crescent-shaped path for the movement path of the spray unit in the inlet area. In the outlet area, the workpiece is then sprayed by the same spray unit or by one of the other spray units of the rotary unit painted over. This also results in a crescent-shaped path which intersects the crescent-shaped path applied in the entry area.

The process described above is preferably repeated several times, with the sickle-shaped tracks being applied to the workpiece in the inlet area and in the outlet area, preferably offset from one another, in order to coat the entire surface of the workpiece. The intersecting, crescent-shaped paths along which the coating agent is applied to the workpiece lead to a homogeneous distribution of the coating agent, which appears particularly uniform to the human eye.

In an advantageous development, the swivel joint has a coating agent channel and a flushing agent channel, which are separated from one another by at least one seal, the coating agent channel being designed to connect the coating agent source to the pump in a fluid-conducting manner, and the flushing agent channel being designed to have a seal on the seal about escaping leakage flow, which contains coating agent from the coating agent channel to absorb.

As already explained above, the swivel joint serves to provide a fluid-conducting connection between the coating medium source of the machine frame and the pump of the rotary unit. This fluid-conducting connection is formed by the coating medium channel, which is partially formed by the fixed pivot part and partially by the rotatable pivot part. Between the swivel joint parts, the coating agent channel has a transition area in which the coating agent passes from the stationary swivel joint part into the rotatable swivel joint part. In this area, the pivot parts are separated from each other, which allows them to rotate relative to each other. However, this separation between the hinge parts is accompanied by the formation of at least one gap or channel formed between them. Such a gap or channel is usually sealed by means of the seal already mentioned above, in order to prevent an uncontrolled escape of coating agent from the swivel joint.

However, in this case it cannot be permanently and completely ruled out that the coating medium escapes as a leakage flow past the seal and out of the coating medium channel.

So that the leakage flow, in relation to its flow direction, does not dry behind the seal between the pivot joint parts and possibly stick them together, the flushing agent channel is formed in the pivot joint. This is arranged in relation to the direction of flow of the leakage flow in such a way that the leakage flow can get past the seal into the flushing agent channel and be flushed away by a flushing agent located therein. Since the pressures in the rinsing agent channel are usually lower than in the coating agent channel, it can be sealed off from its environment in a correspondingly simpler manner. In addition, the sealing of the rinsing agent channel is simplified, since the rinsing agent contains fewer caustic or abrasive components than the coating agent.

It is within the scope of the advantageous development that the swivel joint can have a plurality of coating medium channels, via which a plurality of pumps are connected to a respective coating medium source. Furthermore, it is within the scope of the advantageous development that the swivel joint can have a plurality of flushing agent channels. The rinsing agent channels and the coating agent ducts are each separated from one another in pairs by a seal, with a leakage flow that unavoidably emerging at the seal being able to be flushed away through the respective rinsing agent channel. It is also within the scope of the advantageous development that two coating agent channels are assigned to a common flushing agent channel and are separated from it by means of a leak-prone seal. In this case, the flushing agent channel serves to flush away several leakage streams of different coating agents at the same time.

In an advantageous development, the flushing agent channel is connected to a flushing agent source via a flushing agent inlet on the rotary joint. Furthermore, the Detergent channel connected to a detergent sink via a detergent outlet on the swivel joint.

According to the development described above, the detergent source preferably includes a detergent tank and a detergent pump. The detergent pump is used to convey detergent from the detergent tank into the detergent channel and to circulate it at least in the swivel joint with a preferably adjustable pressure before it is discharged via the detergent outlet to the detergent sink. The detergent sink is preferably at least partially formed by the same detergent tank to which the detergent pump is also connected. It is also within the scope of the advantageous development that a second detergent tank is provided for the detergent sink, into which a non-reusable and contaminated detergent can be drained from the detergent outlet.

In an advantageous development, a temperature sensor is arranged on or in the swivel joint.

In the operation of coating devices, it is common for the coating agent or, for example, the rinsing agent to be flammable. In particular, when the coating agent is sprayed, an explosive mixture of coating agent and air can form. For safety reasons, it is therefore desirable to ensure that those components which are directly or indirectly thermally conductively connected to the flammable coating agent and/or rinsing agent and/or coating agent-air-gas mixture are operated in a temperature range which is below the respective ignition temperature. Since the swivel joint is used both for conducting coating agent and preferably for rinsing agent, safety during operation of the coating device is increased if the temperature in the area of the swivel joint or the temperature of the swivel joint is measured. In particular, it is advantageous if the temperature sensor is arranged in the area of the coating agent channel and/or in the area of the flushing agent channel to record the temperature to be able to detect directly in the areas where there is a risk of ignition. It is also within the scope of the advantageous development that the temperature sensor is arranged in the area of the seals of the swivel joint, since more heat is generated in this area during operation of the swivel joint than in the remaining structure of the swivel joint.

In addition to fire and/or explosion protection, the temperature at or in the swivel joint is also relevant because it affects the viscosity of the coating agent. A measurement of the temperature thus allows at least some conclusions to be drawn about the quality of the coated workpieces. In addition, the quality of the coated workpieces can be positively influenced by suitable temperature control of the swivel joint depending on the measured temperature.

During the operation of the coating device, the temperature sensor transmits the recorded temperatures to the control unit, preferably via the valve device and the rotary feedthrough. In this case, the temperature signal can be present as an analog signal and can be converted into a digital signal by means of the valve device. A field bus connection can be used to transmit the signal that has been converted in this way to the control unit via the rotary joint, so that it can be used to control the coating device. In particular, it is within the scope of the advantageous development that the pump capacity of a detergent pump for delivering the detergent in the detergent channel is adjusted as a function of the temperature signal, so that the detergent delivered can also serve as a coolant. Alternatively, the recorded temperature can be transmitted via the wireless transmitter-receiver arrangement.

In an advantageous development, the rotation unit has a base body in which at least the pump and the valve device are arranged. Furthermore, the rotation unit has a plurality of support arms, on each of which at least one of the spray units, preferably two spray units, is arranged. Preferably, the support arms protrude with respect on the axis of rotation of the rotation unit, in each case radially from the base body.

The base body can be formed from a frame which gives the rotation unit its stability and rigidity. In addition, the base body can have one or more flat cladding elements with which the interior of the base body is opaque and sealed against dirt. The axis of rotation of the rotation unit preferably runs through the base body, heavy components of the rotation unit in particular being arranged in the base body.

The support arm is preferably designed as a lightweight construction, for example as a hollow profile or with a framework structure. Overall, this means that the greatest proportion of the weight of the rotation unit can be concentrated in the area of the rotation axis of the rotation unit. This has a beneficial effect on the dimensioning of the drives that are required to generate the rotational movement. This is because the concentration of weight described above means that less drive power is required in comparison to an even distribution of weight on the rotary unit in order to accelerate the rotary unit. Furthermore, the base body can serve to accommodate bearings for the movable mounting of the rotary unit relative to the machine frame. Advantageously, the bearing of the rotation unit relative to the machine frame is designed in such a way that the height of the rotation unit is adjustable. This is advantageous because it also allows the height of the spray units to be adjusted so that workpieces of different thicknesses in particular can be coated from a uniform distance.

In an advantageous development, the rotary joint and the rotary feedthrough are arranged coaxially with one another along the axis of rotation of the rotary unit, with the rotary feedthrough being located above the rotary joint.

Due to the arrangement of the swivel joint below the rotary feedthrough, the coating agent only has to be conveyed to a minimum required level in the lower area of the rotary unit so that it can be made available for the pump arranged on it.

In an advantageous development, the coating agent source comprises a low-pressure pump and a coating agent tank, the low-pressure pump being arranged in a fluid-conducting manner between the rotary joint and the coating agent tank.

The development described above is based on the finding that the reliability of the supply of coating agent during operation can be increased if a low-pressure pump is provided in addition to the pump of the rotary unit. It is true that the pump of the rotation unit can also be suitable on its own for sucking in the coating medium through the swivel joint by appropriate dimensioning. However, investigations have shown that the pump of the rotation device can be dimensioned significantly smaller if the low-pressure pump is also provided. The smaller dimensioning of the pump, which is arranged on the rotation unit, is associated with a correspondingly smaller installation space and weight required for the rotation unit. If required, a differential pressure between the coating medium channel and the flushing medium channel can be adjusted by means of the additional low-pressure pump in order to generate a pressure gradient between the coating medium channel and the flushing medium channel. Here, the detergent pump can be set, for example, to a pressure of 1.5 bar and the low-pressure pump to a pressure of 2.0 bar. The flushing agent pump and the low-pressure pump are preferably structurally identical double-diaphragm pumps.

Further preferred features and embodiments of the coating device according to the invention are explained below using two exemplary embodiments and the drawings. The exemplary embodiments are merely advantageous configurations of the invention and therefore do not restrict it.

Figur 1

ein erstes Ausführungsbeispiel einer erfindungsgemäß ausgestalteten Beschichtungsvorrichtung in schematischer Darstellung;

Figur 2

ein zweites Ausführungsbeispiel einer erfindungsgemäß ausgestalteten Beschichtungsvorrichtung in schematischer Darstellung.

Show it:

figure 1

a first exemplary embodiment of a coating device designed according to the invention in a schematic representation;

figure 2

a second exemplary embodiment of a coating device designed according to the invention in a schematic representation.

In the figure 1 The coating device 1 shown comprises a machine frame 2 with a workpiece holder 3 on which a workpiece 4 to be coated is arranged. In the example shown, the workpiece 4 is a flat piece of wood which is to be painted evenly on the surface and on the side edges.

Furthermore, a compressed air source 5 , an electrical control unit 6 and an electrical voltage source 7 are arranged on the machine frame 2 . In the illustration shown, the compressed air lines coming from the compressed air source 5 and their branches are shown as solid connecting lines. The electrical control lines coming from the control unit 6 are shown as single-dashed connecting lines. The power lines coming from the electrical voltage source 7 are shown as dot-dash connecting lines.

A coating agent tank 8 , a low-pressure pump 9 , a detergent tank 10 and a detergent pump 11 are also arranged on the machine frame 2 .

The coating device 1 also includes a rotation unit 12 which can be rotated relative to the machine frame 2 and is connected to the components of the stationary machine frame 2 via a rotary joint 13 and a rotary bushing 14 . This is discussed in more detail below.

The rotation unit 12 comprises a base body 15 and a plurality of support arms protruding from the base body 15, of which only one support arm is provided with the reference number 16.

The base body 15 includes a frame, not shown here, which forms an interior space in which a compressed air-operated high-pressure pump 17 and a valve device 18 are arranged. The high-pressure pump 17 is designed as a double membrane pump. In another embodiment, the high-pressure pump 17 can also be designed as a piston pump. The valve device 18 is designed as an electrically controllable valve island.

A spray unit 20 is arranged on each of the support arms 16 and each includes a compressed-air-controlled valve 21 for controlling the dispensing of the coating agent. Furthermore, the spray units 20 each comprise an atomizer unit 22 and a shaping air unit 23.

Furthermore, an adjusting means 24 is arranged on the support arms 16, which is mechanically coupled to a cam track in a manner not shown here and by means of which the pivoting position of a spray unit 20 can be adjusted relative to the workpiece holder 3 and the workpiece 4 located thereon.

In a manner not shown here, the coating device 1 comprises a drive with which the rotary unit 12 can be set into a rotational movement relative to the machine frame 2, in particular relative to the workpiece holder 3 and the workpiece 4 located thereon. In the process, coating agent is discharged from the spray units 20 over the surface of the workpiece 4 .

In the present case, the swivel joint 13 serves to be able to supply the rotary unit 12 , which can be rotated with respect to the machine frame 2 , and the spray units 20 arranged on the rotary unit 12 , with coating agent. For this will the coating agent is conveyed into the swivel joint 13 by means of the low-pressure pump 9 via connection II and thereby reaches a coating agent channel (not shown) of the swivel joint 13. In the example shown, the swivel joint 13 comprises two parts which are connected to one another in a sealing manner and which can be rotated relative to one another. A stationary part of the swivel joint is connected to the machine frame 2 and the other, moving part is connected to the rotation unit 12 .

This design of the swivel joint 13 leads to an unavoidable leakage flow between the stationary and the moving part of the swivel joint 13. Although there is a seal in this area, it cannot be permanently and completely ruled out that the coating medium leaks past the seal and out of the coating medium channel reached. So that the leakage flow, in relation to its flow direction, does not dry behind the seal between the swivel joint parts and possibly stick together, a flushing agent channel is formed in the swivel joint. This is arranged in relation to the direction of flow of the leakage flow in such a way that the leakage flow can get past the seal into the flushing agent channel and be flushed away by flushing agent conveyed therein temporarily or permanently.

The detergent channel extends from port I to port III of the swivel joint 13. Port I is connected to the detergent tank 10 via the detergent pump 11 and is used to supply the detergent to the swivel joint 13. Port III is a drain opening through which the Leakage flow offset detergent back into the detergent tank 10 passes.

The coating agent channel is connected to the suction side of the high-pressure pump 17 on the outlet side. Through the high-pressure pump 17, the coating agent reaches the spray units 20 via distributor lines 19.

The high-pressure pump 17 is operated by compressed air and moves with the rotation unit 12. In order to provide a simple compressed air supply to the high-pressure pump 17 to allow, the rotary feedthrough 14 is used to provide compressed air from the compressed air source 5 for the machine frame 2 rotatable rotation unit 12.

It is a special feature of the coating device 1 shown that the valve device 18 is arranged in the base body 15 of the rotation unit 12 and is designed to controllably distribute the compressed air provided by means of the rotary feedthrough 14 on the rotation unit. For this purpose, the valve device 18 is designed as a valve island and has a distribution bar on which a plurality of pneumatic valves in the form of valve disks (not shown) are arranged. The valve discs can each be selectively locked and unlocked by an electrical control signal. The required control signal is provided by the control unit 6 and also output to the valve device 18 via a signal line of the rotary leadthrough 14 . In addition, the rotary leadthrough 14 has a power line for power transmission, by means of which the valve device 18 is also supplied with electrical energy from the voltage source 7 . On the exhaust air side, the valve device 18 is connected to the valves 21 via a large number of exhaust air connections.

In the exemplary embodiment shown here, the valve device 18 serves to control the valves 21 . For this purpose, the valve device 18 can have comparatively small flow cross sections and can therefore be of compact design. In contrast, the high-pressure pump 17 requires a volume flow for its operation, which cannot be provided by the valve device 18 . Instead, the high-pressure pump 17 is connected to the rotary feedthrough 14 via a pneumatic branching element 30 . In the exemplary embodiment shown, the coating device comprises a total of three branching elements, which are designed as T-pieces and are used to divide a compressed air flow provided through the rotary feedthrough 14 independently of the valve device 18 on the rotary unit 12 .

As in figure 1 shown, the compressed air flow is routed to the high-pressure pump 17 by means of the branching element 30 via a pump pressure regulator 25 . The pump pressure regulator 25 serves to regulate the drive pressure of the high-pressure pump 17 to a desired pressure level. A pressure regulator 26 or 27 is arranged in a corresponding manner between the rotary feedthrough 14 and the atomizer units 22 and between the rotary feedthrough 14 and the shaping air units 23 . The pressure levels can each be set digitally by the control unit 6 . The pressure regulators 25, 26, 27 are connected in terms of energy to the electrical voltage source 7 via a current-conducting connection in the rotary leadthrough 14. A coating medium pressure regulator 29 is arranged in a corresponding manner between the high-pressure pump 17 and a spray unit 20 in each case. For the sake of clarity, the power and signaling connection of the coating medium pressure regulator 29 is not shown.

To monitor the temperature of the swivel joint 13, a temperature sensor 28 is arranged in the area of the coating medium channel of the swivel joint 13, which is connected in terms of energy and signals via the valve device 18 and the swivel joint 14 to the electrical voltage source 7 and to the control unit 6. Alternatively, the temperature sensor 28 can be designed as a temperature-dependent resistor.

In the figure 2 The coating device 1 ′ shown essentially corresponds in terms of its structure to the coating device 1 according to FIG figure 1 . In contrast to the in figure 1 The coating device 1 shown has the coating agent device 1 ′ on a valve device 18 which serves as a central distribution element for compressed air, signals and electrical energy on the rotation unit 12 .

For this purpose, the rotary union 14 according to the statements figure 1 constructed and connected to the valve device 18 pneumatically, in terms of signaling and energy technology.

A compressed air flow directed onto the rotary unit 12 reaches the valve device 18 and can be divided among the pneumatically controlled and/or driven components on the rotary unit 12 depending on the control signals from the control unit 6 . Furthermore, the valve device 18 is designed to output control signals from the control unit 6 directly or in a converted form to other electrically controlled components. In the embodiment shown, the valve device 18 outputs electrical control signals to the pressure regulators 25, 26, 27 and 29.

In addition, the valve device 18 is designed with suitable signal inputs for receiving the temperatures measured by the temperature sensor 28 and outputting them to the control unit 6 . The coating device 1 ′ also has electrically controllable actuating means 24 which are connected to the valve device 18 in terms of signals.

Furthermore, the valve device 18 has electrical connections in order to provide electrical energy for the electrically operated components on the rotation unit 12 . For this purpose, the valve device is connected in terms of energy to the pressure regulators 25, 26, 27, 29, the temperature sensor 28 and the electrically controllable actuating means 24.

Another difference between the coating device 1 'according to figure 2 and according to the coating device 1 figure 1 is that the coating device 1 ′ has a pressure regulator 26 for each of the atomizer units 22 and a pressure regulator 27 for each of the shaping air units 23 .

Claims (15)

Coating device (1,1') for superficially applying a coating agent to a workpiece (4), comprising a machine frame (2) with a workpiece holder (3), a source of coating agent and a source of compressed air (5), further comprising a opposite to the machine frame (2) rotatable rotation unit (12) with at least one pump (17) and a plurality of spray units (20), wherein the at least one pump (17) is connected to the coating medium source on the suction side via a fluid-conducting rotary joint (13) and to the spray units (20) on the pressure side ,
characterized in that
the rotation unit (12) has a pneumatic valve device (18) and the spray units (20) each have a compressed air-controlled valve (21) for controlling the dispensing of coating agent, the valve device (18) on the air inlet side at least via a fluid-conducting rotary leadthrough (14), preferably a single-channel rotary feedthrough connected to the compressed air source (5) and on the exhaust air side to the compressed air-controlled valves (21) of the spray units (20). Coating device according to claim 1,
in which the pump (17) is designed to be operated by compressed air and is connected to the compressed air source (5) at least via the rotary leadthrough (14). Coating device according to claim 1 or 2,
in which the pneumatic valve device (18) can be controlled electrically, the rotary feedthrough (14) has at least one signal line and the machine frame (2) comprises an electrical control unit (6) which, via the rotary feedthrough (14), communicates signals with at least the valve device (18) connected is. Coating device according to one of Claims 1 to 3
in which the rotary feedthrough (14) is designed for electrical energy transmission and the machine frame (2) comprises an electrical voltage source (7) which is connected in terms of energy at least to the valve device (18) via the rotary feedthrough (14). Coating device according to claim 1 or 2,
in which the pneumatic valve device (18) can be controlled electrically and the machine frame (2) comprises an electrical control unit (6), with at least the valve device (18) and the control unit (6) being connected in terms of signals by means of a wireless transmitter-receiver arrangement, and in which a pneumatically operated generator is preferably arranged on the rotation unit (12), which is connected to the compressed air source (5) at least via the rotary feedthrough (14) and is designed to supply at least the valve device (18) with electrical energy. Coating device at least according to claim 2,
in which the pump (17) is connected to the rotary leadthrough (14) via a pump pressure regulator (25) on the supply air side, the pump pressure regulator (25) preferably being designed to be electrically controllable. Coating device according to one of the preceding claims, in which a coating medium pressure regulator (29) is arranged between the pump (17) and at least one spray unit (20), the coating medium pressure regulator (29) preferably being designed to be electrically controllable. Coating device according to one of the preceding claims, in which at least one of the spray units (20) has at least one compressed air-operated atomizer unit (22) for atomizing the coating agent, the atomizer unit (22) at least via the rotary feedthrough (14) is connected to the compressed air source (5), and an atomizer pressure regulator (26) is preferably arranged between the atomizer unit (22) and the rotary feedthrough (18), which atomizer pressure regulator (26) is preferably designed to be electrically controllable. Coating device according to one of the preceding claims, in which at least one of the spraying units (20) has at least one compressed-air-operated air conditioning unit (23) for setting a jet shape of the coating medium discharged from the spraying unit (20), the air conditioning unit (23) being connected at least via the rotary feedthrough (14 ) is connected to the compressed air source (5), and a shaping air pressure regulator (27) is preferably arranged between the shaping air unit (23) and the rotary feedthrough (14), which shaping air pressure regulator (27) is preferably designed to be electrically controllable. Coating device according to one of the preceding claims, in which the rotation unit (12) comprises a plurality of adjusting means (24), on each of which one of the spray units (20) is arranged, wherein the adjusting means (24) are designed to apply a position of the respective spray unit (20) arranged on them relative to the workpiece holder (3), in particular an orientation of the respective spray unit (20), and the adjusting means (24) preferably each comprise at least one electric drive and are preferably designed to be electrically controllable. Coating device according to one of the preceding claims, in which the workpiece holder (3) is designed as a conveyor belt in order to convey the workpiece (4) by means of a linear movement from an inlet area of the machine frame (2) to an outlet area, the spray units (24) at a rotary movement of the rotary unit (12) sweeps over the workpiece (4) conveyed by the conveyor belt in the inlet area and in the outlet area. Coating device according to one of the preceding claims, in which the rotary joint (13) has a coating agent channel and a flushing agent channel, which are separated from one another by at least one seal, the coating agent channel being designed to fluidly connect the coating agent source to the pump (17), wherein the rinsing agent channel is designed to take up a leakage flow exiting at the seal, which contains coating agent from the coating agent duct, and wherein the rinsing agent channel is preferably connected to a rinsing agent source via a rinsing agent inlet on the pivot joint (13) and to a rinsing agent sink via a rinsing agent outlet on the pivot joint. Coating device according to one of the preceding claims, in which at least one temperature sensor (28) is arranged in or on the rotary joint (13). Coating device according to one of the preceding claims, in which the rotation unit (12) has a base body (15), in which at least the pump (17) and the valve device (18) are arranged, and in which the rotation unit (12) also has a plurality of Has support arms (16), on each of which at least one of the spray units (20), preferably two spray units (20), is arranged, with the swivel joint (13) and the rotary leadthrough (14) preferably being coaxial with one another along a rotation axis of the rotation unit (12). are arranged and the rotary union (14) is located above the swivel joint (13). Coating device according to one of the preceding claims, wherein the coating medium source comprises a low-pressure pump (9) and a coating medium tank (8), the low-pressure pump (9) being arranged in a fluid-conducting manner between the swivel joint (13) and the coating medium tank (8).

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