Coating system for coating workpieces with coating material

Description

Technical field

[0001] The invention relates to a coating system for coating workpieces with coating material. The coating material preferably serves as a one-component wet paint or a multi-component wet paint.

[0002] In the field of wet paint coating, a fundamental distinction is made between low-pressure and high-pressure applications.

[0003] When a low-pressure conveyor delivers coating material at low pressure to a low-pressure spray gun, which then coats the workpiece, this is referred to as a low-pressure application. In a low-pressure application, the pressure generated by the conveyor is between 0.5 bar and 8 bar. This pressure is supplied by a suitable pump or pressure vessel.

[0004] However, when a high-pressure conveyor delivers the coating material under high pressure to a high-pressure spray gun, which then coats the workpiece, this is referred to as a high-pressure application. In high-pressure applications, the pressure generated by a high-pressure conveyor ranges between 50 bar and 500 bar. Suitable pumps are used as high-pressure conveyors.

[0005] A fire extinguishing pump system for fire extinguishing and cooling purposes is known from publication EP 0 633 042 A1. The fire extinguishing pump system comprises a low-pressure system with a low-pressure pump, which supplies extinguishing water to a low-pressure hand-held nozzle. The fire extinguishing pump system also includes a high-pressure proportioning system with a high-pressure pump, which allows foam to be mixed with the extinguishing water. The mixture is then supplied via a high-pressure hose reel to a connected high-pressure nozzle. State of the art

[0006] High-pressure pumps are generally known. For example, the operating instructions for "Cobra 40-10 Cobra 40-25 High-Pressure Double Diaphragm Pumps", edition 01 / 2018, from J. Wagner GmbH, describe two high-pressure pumps capable of generating a pressure of 250 bar. The design of these high-pressure double diaphragm pumps is described in the Figures 12 and 13 As shown, this high-pressure conveyor, and indeed all high-pressure conveyors, must, by design and for safety reasons, be connected via appropriately pressure-resistant pipes or hoses. This inherently makes them more robust than low-pressure conveyors, resulting in higher weight, increased material usage, and higher manufacturing costs compared to a low-pressure design.

[0007] Low-pressure coating offers the advantage over high-pressure coating that the coating quality is higher and particularly thin film thicknesses can be achieved. However, low-pressure coating has the disadvantage of generating more overspray and taking longer to coat than high-pressure coating.

[0008] Especially when many different workpieces need to be coated and / or the workpiece sizes vary frequently and / or there are frequently changing surface quality requirements, it may be necessary for the user to have both low-pressure and high-pressure applications available. However, purchasing two coating systems, one for low-pressure and one for high-pressure applications, is expensive. WO2015 / 032465 relates to a device for supplying a coating material, in which a conveying unit and several modification units each have their own operating modes selectable via control signals with local control loops, so that different operating states (e.g., working, rinsing, or circulation mode) of a coating system can be easily predefined centrally and automatically set and maintained decentrally. Description of the invention

[0009] One object of the invention is to provide a coating system for coating workpieces with coating material, which is suitable for operating both a low-pressure coating applicator and a high-pressure coating applicator. Advantageously, the coating system according to the invention ensures the safety of the operating personnel at all times.

[0010] The problem is solved by a coating system for coating workpieces with coating material having the features specified in claim 1.

[0011] The coating system according to the invention for coating workpieces with coating material comprises a low-pressure material feeder for conveying the coating material at low pressure from a storage container. The system also includes a high-pressure material applicator and a high-pressure material feeder for conveying the coating material at high pressure to the high-pressure material applicator. Furthermore, a distributor is provided, which has a distributor inlet and a first and a second distributor outlet, wherein the distributor inlet is connectable to the first distributor outlet and the second distributor outlet. The distributor inlet can be supplied with the coating material from the low-pressure material feeder. The high-pressure material feeder can be supplied with coating material via the first distributor outlet.The system also includes a low-pressure material applicator, which can be supplied with coating material via the second distributor outlet.

[0012] Advantageous further developments of the invention result from the features specified in the dependent patent claims.

[0013] In one embodiment of the coating system according to the invention, a further low-pressure material conveyor is provided. The distributor inlet can also be supplied with the coating material originating from the further low-pressure material conveyor.

[0014] In a possible further development of the aforementioned embodiment, the coating material from the low-pressure material conveyor is applied in addition to the coating material from the other low-pressure material conveyor. This is particularly advantageous for multi-component coatings because it allows the various components of the coating to be combined. For example, paint (the first component of the coating material) from the low-pressure material conveyor and hardener (the second component of the coating material) from the other low-pressure material conveyor can be combined.

[0015] It is also possible to add a third component in the low-pressure section of the system. This component could be, for example, an additional reactant or diluent. The diluent, or simply the thinner, serves to change the viscosity of the conveyed material.

[0016] In another possible embodiment of the aforementioned design, the coating material from the low-pressure material conveyor is applied as an alternative to the coating material from the second low-pressure material conveyor. This is advantageous if the low-pressure material conveyor conveys a first color (coating material 1) and the second low-pressure material conveyor conveys a second color (coating material 2), which differs from the first. In this embodiment, the different colors are transported separately to the distributor inlet.

[0017] In a further embodiment of the coating system according to the invention, a mixer is provided which is connected between the low-pressure material conveyors and the distributor. This is particularly advantageous for multi-component coatings because it allows the material components of the coating originating from the low-pressure material conveyors to be combined and mixed in the low-pressure section of the coating system.

[0018] In another embodiment of the coating system according to the invention, the low-pressure material conveyor is designed and operated in such a way that it generates a pressure of less than 32 bar and preferably less than 20 bar.

[0019] In a further development of the coating system according to the invention, the low-pressure material feeder incorporates a double diaphragm pump. The double diaphragm pump has the advantage of conveying the material with very low shear and therefore without stress. Another advantage of the double diaphragm pump is that, due to its design, it is hermetically sealed, so that no molecules can enter the pump's conveying tract from the outside.

[0020] In another embodiment of the coating system according to the invention, the low-pressure material feeder incorporates a gear pump. The gear pump allows for very precise control of the amount of material to be conveyed. Furthermore, the gear pump enables a particularly constant material flow rate. Both factors contribute to a good coating result.

[0021] It would also be advantageous, for example, to include an additional gear pump in the low-pressure path after the distributor to further improve the coating process.

[0022] In another embodiment of the coating system according to the invention, the low-pressure material conveyor includes a pressure vessel. The pressure prevailing in the pressure vessel can be generated by a pump. The pressure vessel has the advantage that the material pressure it provides is less prone to pulsation than the pressure generated by a pump.

[0023] Preferably, the high-pressure material conveyor in the coating system according to the invention is designed and operated in such a way that it generates a pressure of more than 50 bar.

[0024] In a further development of the coating system according to the invention, the high-pressure material feeder is designed as a piston pump or as a double-diaphragm piston pump. The double-diaphragm piston pump is also referred to as a high-pressure double-diaphragm pump and offers even greater safety compared to the piston pump, as its design allows it to act like a check valve. Higher pressures can be generated with the double-diaphragm piston pump than with the piston pump without compromising operational safety.

[0025] In the coating system according to the invention, the distributor can have a T-piece.

[0026] Alternatively, the distributor in the coating system according to the invention can have an actuator to selectively connect the supply input to either the first output or the second output.

[0027] In one embodiment of the coating system according to the invention, the distributor has a changeover valve.

[0028] Alternatively, the distributor in the coating system according to the invention can have a ball valve.

[0029] Furthermore, the coating system according to the invention can be designed such that the distributor is flushable. This can be achieved by designing the distributor to be free of dead spaces or at least substantially free of dead spaces. Flushability can also be improved if the distributor has smooth surfaces in the material-carrying area. It is also advantageous if the distributor is made of an inert material, such as stainless steel or polytetrafluoroethylene (PTFE). Moreover, the distributor can be flushed or cleaned even more easily if it is designed without packings, i.e., without seals.

[0030] The coating system according to the invention can include a high-pressure line through which the coating material travels from the distributor to the high-pressure material conveyor. This further increases operational reliability. If the high-pressure conveyor conducts the high pressure upstream due to a defect, instead of downstream, the risk of the line bursting is further reduced.

[0031] In one embodiment of the coating system, a low-pressure supply line is provided to supply the distributor with coating material at the inlet. The low-pressure supply line is longer than the high-pressure line. This also serves to increase operational reliability. The longer the low-pressure supply line is compared to the high-pressure line, the longer the material pressure in the system can be maintained in the low-pressure range and only transformed to high pressure when high pressure is actually required.

[0032] To solve the problem, it is further proposed that in the coating system according to the invention a check valve is provided at the downstream end of the supply line that connects the high-pressure conveyor to the distributor.

[0033] Furthermore, it is advantageous if a check valve is provided at the downstream end of the high-pressure line in the coating system according to the invention.

[0034] It is also possible that the coating system according to the invention incorporates two check valves connected in series on the inlet side of the high-pressure material conveyor. This offers the advantage of increased safety through redundancy. This also allows compliance with particularly stringent legal requirements for ensuring operational safety that apply in some regions of the world.

[0035] The coating system according to the invention may be equipped with a rupture disc in the material-carrying low-pressure section. If the rupture disc breaks, the operating personnel are immediately notified that a fault has occurred in the high-pressure section. This also serves to increase the operational reliability of the coating system.

[0036] Advantageously, the coating system has wheels, making it mobile. This allows the system to be used in different locations.

[0037] Furthermore, a coating system is proposed using the coating system described above, in which a robot is provided for manipulating the low-pressure material applicator and / or the high-pressure material applicator. This allows for a further increase in the level of automation.

[0038] In the coating system according to the invention, the mixer can be designed and operated in such a way that the mixing ratio of the material components is adjustable.

[0039] In the coating system according to the invention, the mixer can be designed as a static mixer.

[0040] Furthermore, the coating system according to the invention can include a low-pressure supply line to supply the distributor with coating material at the inlet. Advantageously, the low-pressure supply line does not need to be dimensioned as robustly as a high-pressure line.

[0041] The line through which the coating material travels from the distributor to the low-pressure applicator can also be designed as a low-pressure line.

[0042] Advantageously, the coating system has a control system to control the distributor and / or the mixer and / or the material conveyors.

[0043] In the coating system according to the invention, the low-pressure material applicator and / or the high-pressure material applicator can, for example, be mounted on a robot, a lifting device, or a single- or multi-axis motion device. The same applies analogously to the distributor. Brief description of the drawings

[0044] The invention will now be further explained with several exemplary embodiments and the aid of several figures. Figure 1 shows, in the form of a block diagram, a first possible embodiment of the coating system according to the invention for coating workpieces with coating material. Figure 2 shows, in the form of a block diagram, a second possible embodiment of the coating system according to the invention. Figure 3 shows, in the form of a block diagram, a third possible embodiment of the coating system according to the invention. Figure 4 shows, in the form of a block diagram, a fourth possible embodiment of the coating system according to the invention. Figure 5 shows, in the form of a block diagram, a fifth possible embodiment of the coating system according to the invention. Figure 6 shows, in the form of a block diagram, a first possible embodiment of a high-pressure material conveyor. Figure 7 shows, in the form of a block diagram, a second possible embodiment of a high-pressure material conveyor.Figure 8 shows a possible embodiment of the coating system according to the invention in a three-dimensional view. Figure 9 shows the embodiment according to [reference missing]. Figure 8 Figure 10 shows a side view of the coating system according to the invention. Figure 11 shows a side view of a possible embodiment of a pressure vessel. Figure 12 shows a side view of a possible embodiment of a high-pressure material conveyor, partially in section. Figure 13 shows a section of the color stage of the high-pressure material conveyor. Figure 14 shows a three-dimensional view of a possible embodiment of a changeover valve. Figure 15 shows a front view of the embodiment of the changeover valve. Figure 16 shows a longitudinal section of the changeover valve. Figure 17 shows a cross-section of the changeover valve. Ways to implement the invention

[0045] A first possible embodiment of the coating system according to the invention for coating workpieces with coating material is shown in Figure 1 The coating system is also referred to simply as the system. It comprises a low-pressure material conveyor 1 to convey the coating material 31 from a storage container 21 via a line 61. The coating material 31 is then fed at low pressure via the low-pressure conveyor 1 to a material feed device 10 via a line 71. The storage container 21, the line 61, the low-pressure material conveyor 1, and the line 71 are hereinafter also referred to as the first low-pressure coating stage.

[0046] In addition to the first low-pressure inking stage, the coating system comprises three further low-pressure inking stages. The second low-pressure inking stage includes a storage container 22, a line 62, a low-pressure conveyor 2, and a line 72. The third low-pressure inking stage includes a storage container 23, a line 63, a low-pressure conveyor 3, and a line 73. Finally, the fourth low-pressure inking stage includes a storage container 24, a line 64, a low-pressure conveyor 4, and a line 74. The four low-pressure inking stages can have the same configuration, but this is not mandatory.

[0047] Each of the low-pressure color stages can be intended for a different coating material or a component of the coating material. For example, the first low-pressure color stage can be for a first color, and the second low-pressure color stage for a second color that differs from the first. The third color stage can be for a component of the color, such as the hardener. The fourth color stage can serve as a reserve. Therefore, it is not necessary to use all four color stages simultaneously.

[0048] As in Figure 1As shown, the downstream ends of lines 71, 72, 73, and 74 lead to the material feed device 10. The material feed device 10 is controlled by a higher-level control unit 40 and can, for example, specify via valves which of the materials 31 to 34 is fed into line 81. It can also be provided that the control unit 40 specifies the duration, quantity, or ratio of the materials. The material feed device 10 then opens and closes the valves in lines 71 to 74 accordingly. Figure 3 The figure shows, by way of example, for two color levels, how corresponding valves 17 and 19 are arranged to control the material flow in the two lines 71 and 72.

[0049] On the output side, the material feed device 10 is connected to the supply line 81. This in turn leads to a distributor 11 and is connected to its inlet 11.1. If required, the distributor 11 can be controlled via the control unit 40. The distributor 11, in its configuration as shown, has... Figure 1 The distributor 11 has two outlets, 11.2 and 11.3, which can be connected to the inlet 11.1. The distributor 11 may also have further outlets (not shown in the figures) which can be connected to the inlet 11.1.

[0050] One outlet 11.3 is connected via a line 92 to a low-pressure material applicator 14. The other outlet 11.2 is connected via a line 91 to a high-pressure material conveyor 12. This conveyor serves to convey the coating material, for example the coating material 31, at high pressure via a line 93 to a high-pressure material applicator 13.

[0051] The distributor 11 serves to direct the coating material 31 originating from the low-pressure material conveyor 1 to the high-pressure material conveyor 12 and / or to the low-pressure material applicator 14. Depending on the application, the distributor 11 can be configured differently. Various embodiments of the distributor 11 are explained below.

[0052] A low-pressure coating applicator, low-pressure material applicator, or low-pressure spray applicator is a spraying device designed for operation at low pressure (between 0.5 bar and 8 bar) and used to spray coating material onto the workpiece to be coated. Low-pressure coating applicators can be manual or automatic. The manual spraying device is also known as a spray gun.

[0053] A high-pressure coating applicator, high-pressure material applicator, or high-pressure spray applicator is a spraying device designed for operation in the high-pressure range (between 50 bar and 500 bar) and used to spray coating material onto the workpiece to be coated. Like low-pressure coating applicators, high-pressure coating applicators can be designed as manual or automatic spraying devices.

[0054] Coating applicators can be used that atomize the material, for example, using air and / or hydraulic pressure. If required, the coating applicators can also be equipped with an electrostatic unit to electrostatically charge the coating material. This causes the coating material to be attracted to the workpiece, which is grounded or at a lower electrical potential.

[0055] Wet paint is preferably used as the coating material.

[0056] This can be a single-component or multi-component wet paint. The term "coating material" here should be understood to refer to both the ready-to-use wet paint and a component of the paint, such as the color or the hardener. Therefore, when the term "coating material" is used below, it depends on the context whether it refers to a material component of a multi-component paint or to the ready-to-use multi-component paint itself. 2. embodiment

[0057] A second possible embodiment of the coating system according to the invention is described in Figure 2 This is shown in the form of a block diagram. In this embodiment, there is only one color stage with reservoir 21, line 61 and low-pressure conveyor 1.

[0058] In this embodiment, the distributor 11 comprises a T-piece 11.6. The inlet of the T-piece 11.6 is the distributor inlet 11.1, the first outlet of the T-piece 11.6 is outlet 11.2, and the second outlet of the T-piece 11.6 is outlet 11.3 of the distributor 11. The term T-piece means that the inlet 11.1 is continuously connected to both outlets 11.2 and 11.3 via a connecting channel. The path of the connecting channel can, for example, be T-shaped or Y-shaped.

[0059] The coating system thus configured is suitable for coating the workpieces simultaneously with the low-pressure coating applicator 14 and the high-pressure coating applicator 13, if required. Since each of the coating applicators 13 and 14 has a trigger lever in this embodiment, the operator can select which of the two coating applicators 13 and 14 is to be used to coat the workpiece.

[0060] In this embodiment of the coating system, it is not provided that one or both lines 91 and 92 are depressurized using the distributor 11. If both lines 91 and 92 are to be depressurized, this is done by switching off the low-pressure conveyor 1. 3. embodiment

[0061] A third possible embodiment of the coating system according to the invention is described in Figure 3 represented in the form of a block diagram.

[0062] In this embodiment, the distributor 11 includes an actuator 11.5, which can be controlled via the control unit 40. The actuator 11.5 can be configured to function as a changeover switch. This makes it possible to supply either the low-pressure coating applicator 14 or the high-pressure coating applicator 13 with coating material.

[0063] When the actuator connects the distributor inlet 11.1 to the outlet 11.3 (switching position 1), the low-pressure coating applicator 14 is ready for operation, while the high-pressure section (high-pressure conveyor 12, line 93 and high-pressure coating applicator 13) is completely shut down. This ensures that there is no high pressure anywhere in the high-pressure section and, consequently, no hazards can emanate from it.

[0064] When the actuator connects the distributor inlet 11.1 to the outlet 11.2 (switching position 2), the high-pressure coating applicator 13 is ready for operation, while the low-pressure section (line 92 and low-pressure coating applicator 14) is switched off. In this operating state of the system, the low-pressure coating applicator 14 can be disconnected from line 92 without posing a risk to the operating personnel. Furthermore, the low-pressure coating applicator 14 can be cleaned, for example, in this operating state.

[0065] The actuator 11.5 can also be designed to allow more than two switching positions. For example, in the embodiment of the actuator 11.5 according to Figure 5 Four switch positions can be selected.

[0066] In supply line 81, at the downstream end, as in Figure 3 It is indicated that a check valve 100 should be installed. 4. embodiment

[0067] A fourth possible embodiment of the coating system according to the invention is described in Figure 4 This is shown in the form of a block diagram. Here too, the distributor 11 includes an actuator that can be controlled via the controller 40. Alternatively, the actuator can also be operated manually. The actuator is designed as a 2 / 2-way valve 211.

[0068] In this embodiment, it is possible to supply only the low-pressure coating applicator 14 with coating material and to depressurize the high-pressure section. This ensures that there is no high pressure anywhere in the high-pressure section and, consequently, no hazards can emanate from it.

[0069] When the 2 / 2-way valve 211 is in the first position 211.1 (as in Fig. 4(as shown), it connects the distributor inlet 11.1 with the outlet 11.3. The coating material is now fed to the low-pressure coating applicator 14, which is ready for operation. The high-pressure section (high-pressure conveyor 12, line 93 and high-pressure coating applicator 13), however, is completely depressurized.

[0070] If, however, the 2 / 2-way valve 211 is in the second position 211.2, it connects the distributor inlet 11.1 to the outlet 11.2. The coating material is then fed to the high-pressure conveyor 12 and from there to the high-pressure coating applicator 13. The coating applicator 13 is now ready to coat workpieces. Line 92 and the low-pressure coating applicator 14, on the other hand, are completely depressurized.

[0071] The coating system can, as in Figure 4The diagram also shows a mixer 15. This mixer is connected between the material feed device 10 and the distributor 11. Preferably, the inlet of the mixer 15 is located in the immediate vicinity of the outlet of the material feed device 10. This has the advantage that the dead space can be kept particularly small, which is especially advantageous during color changes.

[0072] Lines 71 and 72 can be of varying lengths as needed. If larger distances need to be bridged between the low-pressure material conveyor 1, 2 and the distributor 11, this is preferably accomplished not with line 81, but with lines 71 and 72. Figure 4 This is indicated. Among other things, this ensures that there is little already mixed material in line 81 and consequently only a small amount of already mixed material needs to be flushed out of line 81 during flushing.

[0073] Another advantage of this design is that the number of components that can come into contact with pre-mixed 2K material is minimized. This significantly reduces the consumption of cleaning agents during rinsing processes.

[0074] Furthermore, in Figure 4 An optional detergent connection 18 is shown. The detergent connection 18 can be accessed via a Figure 4 The rinsing agent reservoir (not shown) is supplied with rinsing agent. With valve 16 open, the coating system can be cleaned or rinsed. For example, rinsing agent can be routed or pumped via the rinsing agent connection 18 through the material feed device 10, the mixer 15, the lines 81, 91, 92, 93, the distributor 11 with its inlets and outlets, the high-pressure conveyor 12, and also through the coating applicators 13, 14.

[0075] The in Figure 4The actuator shown can also be configured with up to four switching positions instead of the 2 / 2-way valve. For this purpose, the actuator can have two 2 / 2-way valves, each of which can be controlled via a control line from the control unit 40, thus enabling a total of four switching positions. In the first switching position, the low-pressure line is open and the high-pressure line is closed. In the second switching position, the low-pressure line is closed and the high-pressure line is open. In the third switching position, both lines are open, and in the fourth switching position, both lines are closed.

[0076] Alternatively, the actuator can also be a 3 / 2-way valve. The actuator can then, for example, allow the following three switching positions: low-pressure line open and high-pressure line closed; low-pressure line closed and high-pressure line open; both lines open. 5. Design

[0077] A fifth possible embodiment of the coating system according to the invention is described in Figure 5 This is shown in the form of a block diagram. Here too, the distributor 11 includes an actuator that can be controlled via the controller 40. The actuator can also be operated manually. The actuator is designed as a 4-way valve 311. The 4-way valve 311 can, for example, be a ball valve.

[0078] If valve 311 is in the first position 311.1 (as in Figure 5(As shown), line 91 is connected to supply line 81, and the coating material is transported to the high-pressure conveyor 12. The high-pressure conveyor 12 brings the coating material to the desired high pressure and supplies the high-pressure coating applicator 13 via line 93. Coating can now be carried out using the high-pressure coating applicator 13. Line 92 and the low-pressure coating applicator 14 are depressurized.

[0079] When valve 311 is in the second position 311.2, both the low-pressure coating applicator 14 and the high-pressure feeder 12 are supplied with coating material. Simultaneous coating is now possible with both the low-pressure coating applicator 14 and the high-pressure coating applicator 13. In position 311.2, valve 311 functionally corresponds to the T-piece 11.6. Figure 2 .

[0080] As in the fourth embodiment according to Figure 4 In the fifth embodiment, it is also possible to supply only the low-pressure coating applicator 14 with coating material and to completely depressurize the high-pressure section. This state is set when the valve 311 is in the third position 311.3. This ensures that there is no high pressure anywhere in the high-pressure section and, consequently, no danger can emanate from the high-pressure section.

[0081] Furthermore, the fourth position 311.4 of the valve 311 ensures that neither the low-pressure coating applicator 14 nor the high-pressure section is pressurized.

[0082] Even at the in Figure 5 In the embodiment shown, the supply line 81 can be located at the downstream end, as shown in Figure 3 It is indicated that a check valve 100 should be installed. 1. Design of the high-pressure material conveyor

[0083] Figure 6Figure 1 shows a first possible embodiment of the high-pressure material conveyor 12 in the form of a block diagram. The high-pressure material conveyor 12 is designed here as a double-diaphragm piston pump 50. The block diagram shows a simplified representation of the construction of a double-diaphragm piston pump 50. The double-diaphragm piston pump 50 has two inlet valves 51 and 52, a cylinder 53, a piston 54 movably arranged in the cylinder 53, two diaphragms 55.1 and 55.2, and two outlet valves 57 and 58. The piston 54 is connected to a motor 56, for example an air motor, via a piston rod and is driven by it. The piston 54 acts on the two diaphragms 55.1 and 55.2. Diaphragm 55.1 forms an upper pumping chamber 59.1 with the housing, and diaphragm 55.2 forms a lower pumping chamber 59.2 with the housing. The four valves 51, 52, 57 and 58 are designed as check valves. This has the advantage that they can close automatically.

[0084] The double-diaphragm piston pump 50 is supplied with coating material at low pressure via supply line 91. When the piston 54 moves downwards in the cylinder 53, the first diaphragm 55.1 is pulled downwards, the upper pump chamber 59.1 expands, and coating material is drawn into the upper pump chamber 59.1 via the inlet valve 51. Simultaneously, as the piston 54 moves downwards, the second diaphragm 55.2 is pushed downwards, the lower pump chamber 59.2 contracts, and the coating material contained therein is forced into line 93 via the outlet valve 58. The inlet valve 52 remains closed during this process. When the piston 54 moves upwards again after passing the bottom reversal point, the inlet valve 51 closes, and coating material is drawn into the now expanding lower pump chamber 59.2 via the now open inlet valve 52. The exhaust valve 58 is closed.At the same time, during the upward movement of the piston 54, the volume of the upper pump chamber 59.1 is reduced and the coating material contained therein is forced into the line 93 via the now open outlet valve 57.

[0085] If the inlet valve 51 of the piston double diaphragm pump is permanently open due to a defect, the coating material is pumped under pressure into the common delivery channel 91 during the operating cycle of the upper pump chamber 59.1. The forced and simultaneous suction cycle of the lower pump chamber 59.2 actively draws the pressurized material into the lower, pressure-resistant pump chamber 59.2. This effectively prevents impermissible pressure loads on upstream components, such as the line 91 and the distributor 11 (not shown in Figure 6).

[0086] The same applies, in essence, if the inlet valve 52 is permanently open due to a defect.

[0087] A check valve 150 may be provided in the area of ​​the pump inlet 50.1, which forms the common intake channel of the double-diaphragm piston pump 50. However, due to the two check inlet valves 51 and 52 arranged in the same direction and opening alternately, the additional, redundant check valve 150 is not strictly necessary.

[0088] The same applies analogously to other pumps if they have two inlet-side, symmetrically arranged, alternately opening non-return valves, these inlet valves being connected to each other via a common suction channel (line 91 or delivery channel in the pump housing). 2. Design of the high-pressure material conveyor

[0089] Figure 7Figure 1 shows a second possible embodiment of the high-pressure material conveyor 12 in the form of a block diagram. Here, the high-pressure material conveyor 12 is designed as a double-acting piston pump 110. During the downward movement of the working piston 114, driven by a drive piston 115, material previously drawn into the lower pump chamber 113.1 is conveyed, with the non-return inlet valve 112 closed, via the overflow channel 114.1 and the open non-return overflow valve 117 into the upper pump chamber 113.2. From there, the material is conveyed to the pump outlet and thus into line 93 during the next upward movement of the working piston 114.

[0090] It is assumed that, due to a defect, the check inlet valve 112 is permanently open. During the downward movement of the working piston 114, material previously drawn into the lower pump chamber 113.1 is transported at least partially through the intake channel 119 via the open check inlet valve 112 at high pressure. To prevent the resulting impermissible pressure load on upstream components, a second, redundant check valve 111 is arranged in the intake channel 119, 91. This prevents material under high pressure from flowing back into the line 91.

[0091] Therefore, it is advantageous to provide check valves that ensure redundancy in case of a defect. These check valves can operate in parallel and in opposite directions, as in the piston double diaphragm pump in Figure 6 shown. However, the check valves can also operate sequentially and in the same direction, as in the piston pump according to Figure 7 .

[0092] Figure 8 shows a possible embodiment of the coating system in a three-dimensional view. Figure 9 The coating system is shown in side view. The coating system comprises a frame 540 mounted on wheels 550. The frame 540 is designed to allow for variable loading. In the Figure 8The variant shown features six identical low-pressure conveyors 501 to 506 and one high-pressure conveyor 400. If required, the frame 540 can also be equipped with, for example, one fewer low-pressure conveyor and one more high-pressure conveyor. It is also easily possible to mount different low-pressure conveyors on the frame 540. The lower section of the frame 540 has a grid floor. Various storage containers 21, 22, 23, for example, can be placed on it. It is also possible to mount a pressure vessel 410 (see Figures 10 and 11 ) to arrange on the frame 540 (in Figure 8 (not shown). The pressure vessel 410 can, for example, be used to convey the material instead of one of the low-pressure conveyors 501 to 506. The control unit 40 can be arranged to the side of the frame 540. It can be, as shown in Figure 8As shown, the control unit 40 is arranged on a separate, mobile frame 560. This allows the operating personnel to position the control unit 40 independently of the frame 540 in the best possible way.

[0093] In Figure 10 is a possible embodiment of the pressure vessel 410 in side view and in Figure 11 The pressure vessel 410 is shown in a three-dimensional view. It is used to convey the material and can replace a low-pressure pump. The pressure vessel 410 allows for pulsation-free and low-shear conveyance of the material.

[0094] The high-pressure material conveyor 12 can, for example, be a high-pressure double diaphragm pump. One possible embodiment of such a high-pressure double diaphragm pump 50 is Figure 12 The side view shows a section of the pump. It is a high-pressure double diaphragm pump, sold by J. Wagner GmbH under the product name "Cobra".

[0095] The color grade 403 of the high-pressure double diaphragm pump 50 is in Figure 13 The cross-section shows the paint stage 403 of the high-pressure double diaphragm pump 50. This is the part of the pump into which the paint is drawn and from which the high-pressure paint is expelled. Paint stage 403 is therefore the part of the pump that comes into contact with the paint and must be cleaned when changing colors.

[0096] The high-pressure double diaphragm pump 50 has a pump inlet 50.1 for connection to line 91 (not shown in the figure). From the pump inlet 50.1, the coating material passes to a first inlet valve 51 and a second inlet valve 52. The portion of the material that passes through the inlet valve 51 enters the first pump chamber, the volume of which can be changed by means of a first diaphragm 401. The other portion of the material passes through the inlet valve 52 into the second pump chamber, the volume of which can be changed by means of a second diaphragm 402. The two diaphragms 401 and 402 are moved synchronously by means of a piston rod 54. The material from the first pump chamber passes through an outlet valve 57 into the outlet channel 403.1 and from there to line 93. The material from the second pump chamber also passes through an outlet valve 58 into the outlet channel 403.1.The two inlet valves 51 and 52 and the two outlet valves 57 and 58 are designed as check valves.

[0097] The operating principle of the high-pressure double diaphragm pump 50 is shown in the block diagram in Figure 6 This was shown and already described above at the relevant point. To avoid repetition, we will refer to... Figure 6 and the corresponding description is referenced.

[0098] Figure 14 shows a possible embodiment of a changeover valve in a three-dimensional view. Figure 15 is the changeover valve from the front, in Figure 16 in longitudinal section and in Figure 17 shown in cross-section. The valve 211 installed in distributor 11 can be constructed like the changeover valve 600. It has a first valve needle 601 and a second valve needle 602. If the first valve needle 601 (see Figure 16When the second valve needle 602 is moved to the left, it opens the first material channel, and the material flows from the inlet 11.1 via a channel 603 to the first outlet 11.2. When the second valve needle 602 is moved to the right, it opens the second material channel, and the material flows from the inlet 11.1 via the channel 603 to the second outlet 11.3.

[0099] In the coating system according to the invention, it is advantageous to design the long material-carrying lines and, if a color-changing and a mixing system are present, also these as low-pressure systems. The transformation to high pressures advantageously takes place only shortly before the high-pressure coating applicator(s) 13 with the aid of the intermediate high-pressure conveyor 12.

[0100] Piston diaphragm pumps are particularly suitable as high-pressure conveying devices. They exert only extremely low shear forces on the coating material, are hermetically sealed from the environment, generate only low pulsation, and draw in the coating material evenly.

[0101] If only a piston diaphragm pump is used for the high-pressure conveyor 12, the cleaning agent consumption for cleaning the coating system increases only slightly. This is due to the typically very small pump chamber volume of piston diaphragm pumps.

[0102] Diaphragm pumps are suitable as low-pressure conveying systems. Designing the low-pressure conveying systems as diaphragm pumps has the advantage that the coating system can be easily rinsed and cleaned with little solvent.

[0103] The coating system according to the invention is also suitable for processing critical materials, such as UV-curing lacquers or two-component materials with isocyanate-based hardeners.

[0104] The high-pressure piston pump according to Figure 7 It can be designed to pump highly viscous materials with a high solids content. Diaphragm pumps are typically less suitable for this purpose.

[0105] It is also possible to configure pump 1 as a piston pump 110. Even though the piston pump 110 is designed as a high-pressure piston pump, it can be operated at low pressures. The advantage of the piston pump 110 is its high suction capacity. The material flow is then fed, if necessary after passing through the mixer 15, directly to the low-pressure material applicator 14 via the diverter valve in the distributor 11, or to the high-pressure material applicator 13 via the high-pressure material feeder 12 (booster pump). This configuration is suitable for processing heavy materials and can utilize the advantage of a booster pump, namely its high suction capacity.

[0106] The piston pump 110 can be configured with a high gear ratio and can then generate high pressures. This variant of the piston pump 110 is also known as a high-pressure piston pump. If the piston pump 110 is configured with a low gear ratio (low-pressure piston pump), it generates a lower pressure than the high-pressure piston pump but has a higher suction capacity. The piston pump 110 is generally not hermetically sealed and causes higher material shear than the piston diaphragm pump 50.

[0107] The preceding description of the embodiments according to the present invention serves only for illustrative purposes. For example, one of the embodiments described in the Figures 2 , 3 , 4 and 5 The illustrated embodiments of the distributor 11 also apply to the coating system according to Figure 1 to be used.

[0108] One or both of the applicators 13 and 14 and, if applicable, the distributor 11 can be used on a robot, a lifting device or a single- or multi-axis motion device (not shown in the figures). Reference symbol list

[0109] 1 Low-pressure material conveyor 2 Low-pressure material conveyor 3 Low-pressure material conveyor 4 Low-pressure material conveyor 10 Material feed device 11 Distributor 11.1 Distributor inlet 11.2 Distributor outlet 11.3 Distributor outlet 11.5 Actuator 11.6 T-piece 12 High-pressure material feeder 13 High-pressure material applicator 14 Low-pressure material applicator 15 Mixer 16 Valve 17 Valve 18 Washing agent connection 19 Valve 21 Reservoir 22 Reservoir 23 Reservoir 24 Reservoir 31 Coating material 32 Coating material 33 Coating material 34 Coating material 40 Control 50 Piston double diaphragm pump (high-pressure double diaphragm pump) 50.1Pump inlet 51 Inlet valve 52 Inlet valve 53 Cylinder 54 Piston 55.1 First diaphragm 55.2 Second diaphragm 56 Motor 57 Outlet valve 58 Outlet valve 59.1 Pump chamber 59.2 Pump chamber 61 Line 62 Line 63 Line 64 Line 71 Line 72 Line 73 Line 74 Line 81 Supply line 91 Line 92 Line 93 Line 100 Check valve 110 Piston pump 111 Check valve 112 Check inlet valve 113 Cylinder 113.1 Lower pump chamber 113.2 Upper pump chamber 114 Piston 114.1 Overflow channel 115 Cylinder 116 Motor 117 Check valve 119 Intake channel 150 Check valve 2112 / 2-way valve 211.1 first valve position 211.2 second valve position 3114-way valve 311.1 first valve position 311.2 second valve position 311.3 third valve position 311.4 fourth valve position 400 High-pressure double diaphragm pump 401 Diaphragm 402 Diaphragm 403 Color stage 403.1 Outlet channel 410 Pressure vessel 501 Low-pressure conveyor 502 Low-pressure conveyor 503 Low-pressure conveyor 504 Low-pressure conveyor 505 Low-pressure conveyor 506 Low-pressure conveyor 540 Frame 550 Wheel 560 Frame 600 Changeover valve 601 Valve needle 602 Valve needle 603 Channel.

Claims

1. A coating assembly for coating workpieces with coating material, - in the case of which a low pressure material conveyor (1) is provided in order to convey the coating material (31) at low pressure from a storage container (21), - in the case of which a high pressure material applicator (13) and a high pressure material conveyor (12) for conveying the coating material (31) at high pressure to the high pressure material applicator (13) are provided, - in the case of which a manifold (11) is provided, which has a manifold inlet (11.1) as well as a first and a second manifold outlet (11.2; 11.3), - in the case of which the coating material (31) originating from the low pressure material conveyor (1) can be applied to the manifold inlet (11.1), - in the case of which the high pressure material conveyor (12) can be supplied with coating material via the first manifold outlet (11.2) and - in the case of which a low pressure material applicator (14) is provided, which can be supplied with coating material via the second manifold outlet (11.3), characterized in that the manifold (11) has an actuator (11.5) in order to optionally connect the manifold inlet (11.1) to the first manifold outlet (11.2) or to the second manifold outlet (11.3).

2. The coating assembly according to patent claim 1, - in the case of which a further low pressure material conveyor (2) is provided, - in the case of which the coating material (31) originating from the further low pressure material conveyor (2) can be applied to the manifold inlet (11.1).

3. The coating assembly according to patent claim 2, in the case of which a mixer (15) is provided, which is switched between the low pressure material conveyors (1; 2) and the manifold (11).

4. The coating assembly according to any one of patent claims 1 to 3, in the case of which the low pressure material conveyor (1) is formed and operable in such a way that it generates a pressure of less than 32 bar and preferably of less than 20 bar.

5. The coating assembly according to any one of the preceding patent claims, in the case of which the low pressure material conveyor (1) is formed as double diaphragm pump (400).

6. The coating assembly according to any one of patent claims 1 to 4, in the case of which the low pressure material conveyor (1) has a gear pump.

7. The coating assembly according to any one of the preceding patent claims, in the case of which the low pressure material conveyor (1) has a pressure container (410).

8. The coating assembly according to any one of patent claims 1 to 3, in the case of which the high pressure material conveyor (12) is formed and operable in such a way that it generates a pressure of more than 50 bar.

9. The coating assembly according to any one of the preceding patent claims, in the case of which the high pressure material conveyor (12) is formed as piston pump or as piston double diaphragm pump.

10. The coating assembly according to any one of patent claims 1 to 8, in the case of which the manifold (11) has a shuttle valve (211).

11. The coating assembly according to any one of patent claims 1 to 8, in the case of which the manifold (11) has a ball valve (311).

12. The coating assembly according to any one of the preceding patent claims, in the case of which a high pressure line (91) is provided, via which the coating material reaches from the manifold (11) to the high pressure material conveyor (12).

13. The coating assembly according to patent claim 12, - in the case of which a low pressure supply line (81) is provided in order to supply the manifold (11) with coating material on the input side, - in the case of which the low pressure supply line (81) is longer than the high pressure line (91).

14. The coating assembly according to patent claim 13, in the case of which a non-return valve (100) is provided on the downstream end of the supply line (81).

15. The coating assembly according to any one of patent claims 13 or 14, in the case of which a non-return valve (51, 52; 61) is provided on the downstream end of the high pressure line (91).

16. The coating assembly according to any one of patent claims 13 to 15, in the case of which two non-return valves (61; 62), which are connected in series, are provided on the inlet side of the high pressure material conveyor (12).

17. The coating assembly according to any one of patent claims 14 to 16, in the case of which the non-return valve (100) has a burst disk.

18. The coating assembly according to any one of the preceding patent claims, in the case of which wheels (550) for moving the coating assembly are provided.

19. A coating system with a coating assembly according to any one of patent claims 1 to 18, in the case of which a robot for manipulating the low pressure material applicator (14) and / or the high pressure material applicator (13) is provided.