COATING DEVICE

Abstract

A coating device for applying a coating agent to the surface of a workpiece. The coating device includes a frame having a workpiece receptacle, a coating agent source, a compressed air source, and a rotary unit which is rotatable in relation to the frame. The rotary unit has a pump and a plurality of spray units, the pump on the suction side being connected to the coating agent source by a fluid-conducting rotary joint connection, and on the pressure side being connected to the spray units. The rotary unit has a pneumatic valve device, and the spray units have in each case one compressed air controlled valve for controlling the delivery of coating agent. The valve on the inlet side is connected to the compressed air source by a fluid-conducting rotary feedthrough and on the exhaust air side is connected to the compressed air controlled valves of the spray units.

Claims

1. A coating device for applying a coating agent to the surface of a workpiece, the coating device comprising: a machine frame having a workpiece receptacle, a coating agent source and a compressed air source, a rotary unit which is rotatable in relation to the machine frame and has at least one pump and a plurality of spray units, the at least one pump on a suction side being connected to the coating agent source by a fluid-conducting rotary joint, and on a pressure side being connected to the spray units, and the rotary unit has a pneumatic valve device, and the spray units each have a compressed air controlled valve for controlling the delivery of coating agent, the pneumatic valve device on an intake air side is connected to the compressed air source at least by way of a fluid-conducting rotary feedthrough, and on an exhaust air side is connected to the compressed air controlled valves of the spray units.

2. The coating device as claimed in claim 1, wherein the pump is configured to be operated by compressed air, and is connected to the compressed air source at least by way of the rotary feedthrough.

3. The coating device as claimed in claim 1, wherein the pneumatic valve device is electrically controllable, the rotary feedthrough has at least one signal line, and the machine frame comprises an electric control unit which for transmitting signals is connected at least to the valve device by the rotary feedthrough.

4. The coating device as claimed in claim 1, wherein the rotary feedthrough is configured for transmitting electric power, and the machine frame comprises an electric voltage source which for transmitting power is connected at least to the valve device by the rotary feedthrough.

5. The coating device as claimed in claim 1, wherein the pneumatic vale device is electrically controllable, and the machine frame comprises an electric control unit, and at least the valve device and the control unit are connected by a wireless transceiver for signal transmission.

6. The coating device as claimed in claim 5, further comprising a pneumatically operated generator disposed on the rotary unit, said pneumatically operated generator at least being connected to the compressed air source by way of the rotary feedthrough and being configured to supply at least the valve device with electric power.

7. The coating device as claimed in claim 2, wherein the pump on the suction side is connected to the rotary feedthrough by a pump pressure regulator, and the pump pressure regulator is electrically controllable.

8. The coating device as claimed in claim 1, wherein a coating agent pressure regulator is disposed between the pump and at least one of the spray units, and the coating agent pressure regulator is electrically controllable.

9. The coating device as claimed in claim 1, wherein at least one of the spray units has at least one compressed air operated atomizer unit to atomize the coating agent, and the atomizer unit is connected to the compressed air source at least by way of the rotary feedthrough.

10. The coating device as claimed in claim 9, further comprising an atomizer pressure regulator which is electrically controllable is disposed between the atomizer unit and the rotary feedthrough.

11. The coating device as claimed in claim 1, wherein at least one of the spray units has at least one compressed air operated forming-air air unit that adjusts a jet shape of the coating agent delivered from the spray unit, and the forming-air air unit is connected to the compressed air source at least by way of the rotary feedthrough.

12. The coating device as claimed in claim 11, further comprising a forming-air pressure regulator which is electrically controllable is disposed between the forming-air air unit and the rotary feedthrough.

13. The coating device as claimed in claim 1, wherein the rotary unit comprises a plurality of actuators on each of which is disposed one of the spray units, the actuators being configured to adjust a status of the respective spray unit disposed thereon in relation to the workpiece receptacle.

14. The coating device as claimed in claim 13, wherein the actuators comprise in each case at least one electric drive and are electrically controllable.

15. The coating device as claimed in claim 1, wherein the workpiece receptacle comprises a conveyor belt that is configured to convey a workpiece via a linear movement from an inlet region of the machine frame to an outlet region, and the spray units are configured to move in a rotating movement via the rotary unit in a sweeping across the workpiece conveyed by the conveyor belt in the inlet region and in the outlet region.

16. The coating device as claimed in claim 1, wherein the rotary joint has a coating agent channel and a rinsing agent channel which are isolated from one another by at least one seal, the coating agent channel being configured to fluidically connect the coating agent source to the pump, and the rinsing agent channel being configured to receive a leakage flow which exits at the seal and contains coating agent from the coating agent channel.

17. The coating device as claimed in claim 16, wherein the rinsing agent channel is connected to a rinsing agent source by a rinsing agent infeed on the rotary joint, and the rinsing agent channel is connected to a rinsing agent sink by a rinsing agent outlet on the rotary joint.

18. The coating device as claimed in claim 1, further comprising at least one temperature sensor disposed in or on the rotary joint.

19. The coating device as claimed in claim 1, wherein the rotary unit has a main body in which at least the pump and the valve device are disposed, and the rotary unit includes a plurality of support arms on each of which is disposed at least one of the spray units.

20. The coating device as claimed in claim 1, wherein the rotary joint and the rotary feedthrough are disposed so as to be mutually coaxial along a rotation axis of the rotary unit, and the rotary feedthrough is situated above the rotary joint.

21. The coating device as claimed in claim 1, wherein the coating agent source comprises a low-pressure pump and a coating agent tank, and the low-pressure pump is fluidically disposed between the rotary joint and the coating agent tank.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Further preferred features and embodiments of the coating device according to the invention will be explained hereunder by two exemplary embodiments and the drawings. The exemplary embodiments are merely advantageous design embodiments of the invention and thus do not limit the latter.

[0093] In the drawings:

[0094] FIG. 1 shows a first exemplary embodiment of a coating device designed according to the invention, in a schematic illustration; and

[0095] FIG. 2 shows a second exemplary embodiment of a coating device designed according to the invention, in a schematic illustration.

DETAILED DESCRIPTION

[0096] The coating device 1 shown in FIG. 1 comprises a machine frame 2 having a workpiece receptacle 3 on which a workpiece 4 to be coated is disposed. The workpiece 4 in the example shown is a planar timber part which is to be uniformly varnished on the surface and on the lateral edges.

[0097] Furthermore disposed in the machine frame 2 are a compressed air source 5, an electric control unit 6 as well as an electric voltage source 7. The compressed air lines emanating from the compressed air source 5, and the branches of said compressed air lines are illustrated as solid connecting lines in the illustration shown. The electric control lines emanating from the control unit 6 are illustrated as simple dashed connecting lines. The current lines emanating from the electric voltage source 7 are illustrated as chain-dotted connecting lines.

[0098] Disposed on the machine frame 2 are also a coating agent tank 8, a low-pressure pump 9, a rinsing agent tank 10 and a rinsing agent pump 11.

[0099] The coating device 1 furthermore comprises a rotary unit 12 which is rotatable in relation to the machine frame 2 and by way of a rotary joint 13 as well as a rotary feedthrough 14 is connected to the components of the stationary machine frame 2. This will be discussed in detail further below.

[0100] The rotary unit 12 comprises a main body 15 as well as a plurality of support arms which protrude from the main body 15 and of which only one support arm is provided with the reference sign 16.

[0101] The main body 15 comprises a frame, not illustrated here, which configures an interior in which a compressed air operated high-pressure pump 17 as well as a valve device 18 are disposed. The high-pressure pump 17 is designed as a double diaphragm pump. In other embodiments, 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.

[0102] One spray unit 20, which comprises in each case a compressed air controlled valve 21 for controlling the coating agent delivery, is disposed on each of the support arms 16. Furthermore, the spray units 20 comprise in each case one atomizer unit 22 as well as one forming-air unit 23.

[0103] Furthermore, disposed on each of the support arms 16 is an actuators (or actuator) 24 which in a manner not shown here is mechanically coupled to a cam track and by which the pivoted status of a respective spray unit 20 in relation to the workpiece receptacle 3 and the workpiece 4 situated on the latter can be adjusted.

[0104] In the manner not shown here, the coating device 1 comprises a drive by way of which the rotary unit 12 can be set in a rotating motion in relation to the machine frame 2, in particular in relation to the workpiece receptacle 3 and the workpiece 4 situated on the latter. In the process, coating agent from the spray units 20 is delivered across the surface of the workpiece 4.

[0105] The rotary joint 13 presently serves toward being able to supply the rotary unit 12 rotatable in relation to the machine frame 2, and the spray units 20 disposed on the rotary unit 12, with coating agent. For this purpose, the coating agent by the low-pressure pump 9 is conveyed into the rotary joint 13 by way of the connector II, said coating agent hereby making its way into a coating agent channel (not shown) of the rotary joint 13. The rotary joint 13 in the example shown comprises two parts which are connected to one another in a sealing manner and which are rotatable relative to one another. One stationary part of the rotary joint here is connected to the machine frame 2, and the other movable part is connected to the rotary unit 12.

[0106] This construction of the rotary joint 13 leads to an unavoidable leakage flow between the stationary part and the movable part of the rotary joint 13. While a seal is situated in this region, it can however not be permanently and completely precluded that coating agent as a leakage flow makes its way from the coating agent channel so as to bypass the seal. In order for the leakage flow in terms of the flow direction thereof not to dry between the rotary joint parts behind the seal and to potentially adhesively bond said rotary joint parts, a rinsing agent channel is configured in the rotary joint. This rinsing agent channel in terms of the flow direction of the leakage flow is disposed in such a manner that the leakage flow can make its way past the seal into the rinsing agent channel and can be rinsed away by a rinsing agent which is temporarily or permanently conveyed in said rinsing agent channel.

[0107] The rinsing agent channel extends from the connector I to the connector III of the rotary joint 13. The connector I is connected to the rinsing agent tank 10 by way of the rinsing agent pump 11, and serves for feeding the rinsing agent into the rotary joint 13. The connector III represents a drain opening by way of which the rinsing agent mixed with the removed leakage flow makes its way back into the rinsing agent tank 10 again.

[0108] The coating agent channel on the outlet side is connected to the suction side of the high-pressure pump 17. The coating agent by way of the high-pressure pump 17 makes its way to the spray units 20 via distributor lines 19.

[0109] The high-pressure pump 17 is operated by compressed air and moves conjointly with the rotary unit 12. In order to enable a simple supply of compressed air to the high-pressure pump 17, the rotary feedthrough 14 serves for providing compressed air from the compressed air source 5 for the rotary unit 12 which is rotatable in relation to the machine frame 2.

[0110] It is a peculiarity of the coating device 1 shown that the valve device 18 is disposed on the main body 15 of the rotary unit 12 and is designed for distributing in a controllable manner the compressed air provided by the rotary feedthrough 14 to the rotary unit. For this purpose, the valve device 18 is designed as a valve island and has a distributor rail on which a plurality of pneumatic valves in the form of valve disks (not shown) are disposed. The valve disks are in each case selectively able to be blocked and unblocked by an electric control signal. The required control signal is provided by the control unit 6 and by way of a signal line of the rotary feedthrough 14 likewise emitted to the valve device 18. Moreover, the rotary feedthrough 14 has a current line for transmitting power, by which the valve device 18 is also supplied with electric power from the voltage source 7. The valve device 18 on the exhaust air side by way of a multiplicity of exhaust air connectors is connected to the valves 21.

[0111] The valve device 18 in the exemplary embodiment shown here serves for controlling the valves 21. For this purpose, the valve device 18 can have comparatively minor flow cross sections and be of a compact construction as a result. In contrast, the high-pressure pump 17 for the operation thereof requires a volumetric flow which cannot be provided by the valve device 18. Instead, the high-pressure pump 17 by way of a pneumatic branching member 30 is connected to the rotary feedthrough 14. In the exemplary embodiment shown, the coating device comprises a total of three branching members which are embodied as T-pieces and serve for subdividing on the rotary unit 12 a compressed air flow, which is provided by the rotary feedthrough 14, independently of the valve device 18.

[0112] As is shown in FIG. 1, the compressed air flow by the branching member 30 is directed to the high-pressure pump 17 by way of a pump pressure regulator 25. The pump pressure regulator 25 serves for regulating the drive pressure of the high-pressure pump 17 to a desirable pressure level. In an analogous manner, one pressure regulator 26 or 27, respectively, is in each case disposed between the rotary feedthrough 14 and the atomizer units 22, as well as between the rotary feedthrough 14 and the forming-air units 23. The pressure levels here are in each case digitally adjustable by the control unit 6. The pressure regulators 25, 26, 27 for transmitting power are connected to the electric voltage source 7 by way of a current-conducting connection in the rotary feedthrough 14. A coating agent pressure regulator 29 is disposed in an analogous manner between the high-pressure pump 17 and a respective spray unit 20. The connection of the coating agent pressure regulator 29 for transmitting power and signals is not illustrated for the sake of improved clarity.

[0113] A temperature sensor 28 for monitoring the temperature of the rotary joint 13 is disposed in the region of the coating agent channel of the rotary joint 13, said temperature sensor 28 for transmitting power and signals being connected to the electric voltage source 7, or to the control unit 6, respectively, by way of the valve device 18 and the rotary joint 14. Alternatively, the temperature sensor 28 can be designed as a temperature-dependent resistor.

[0114] The coating device 1′ shown in FIG. 2 in terms of the construction thereof corresponds substantially to the coating device 1 according to FIG. 1. As opposed to the coating device 1 shown in FIG. 1, the coating agent device 1′ has a valve device 18 which on the rotary unit 12 serves as a central distributor element four compressed air, signals and electric power.

[0115] To this end, the rotary feedthrough 14 is constructed in a manner corresponding to the embodiments pertaining to FIG. 1, and in terms of pneumatics, signals and power is connected to the valve device 18.

[0116] A compressed air flow guided to the rotary unit 12 makes its way into the valve device 18 and, as a function of the control signals of the control unit 6, can be divided among the pneumatically controlled and/or driven components on the rotary unit 12. Furthermore, the valve device 18 is designed to emit control signals of the control unit 6 directly or in a modified form to other electrically controlled components. In the exemplary embodiment shown, the valve device 18 emits electric control signals to the pressure regulators 25, 26, 27 and 29.

[0117] Moreover, the valve device 18 by way of suitable signal inputs is designed to receive the temperatures measured by the temperature sensor 28 and to emit said temperatures to the control unit 6. The coating device 1′ furthermore has electrically controllable actuators (or an electrically controllable actuator) 24 which for transmitting signals are connected to the valve device 18.

[0118] The valve device 18 furthermore has electrical connectors for providing electric power to the electrically operated components on the rotary unit 12. For this purpose, the valve device for transmitting power is connected to the pressure regulators 25, 26, 27, 29, to the temperature sensor 28 as well as to the electrically controllable actuators 24.

[0119] A further difference between the coating device 1′ according to FIG. 2 and the coating device 1 according to FIG. 1 lies in that the coating device 1′ for the atomizer units 22 has in each case one pressure regulator 26 and for the forming-air units 23 has in each case one pressure regulator 27.