EP3936235A1 - Coating assembly for coating workpieces with coating material - Google Patents

Abstract

The coating system according to the invention for coating workpieces with coating material comprises a low-pressure material conveyor (1) in order to convey the coating material (31) at low pressure from a storage container (21). The system also includes 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). Furthermore, a distributor (11) is provided, which has a distributor inlet (11.1) and a first and a second distributor outlet (11.2; 11.3), the distributor inlet (11.1) being connected to the first distributor outlet (11.2) and the second distributor outlet (11.3) is connectable. The distributor inlet (11.1) can be charged with the coating material (31) coming from the low-pressure material conveyor (1). The high-pressure material conveyor (12) can be supplied with coating material via the first distributor outlet (11.2). The system also includes a low-pressure material applicator (14) which can be supplied with coating material via the second distributor outlet (11.3).

Description

technical field

The invention relates to a coating system for coating workpieces with coating material. One-component wet paint or multi-component wet paint is preferably used as the coating material.

In the field of liquid paint coating, a basic distinction is made between low-pressure and high-pressure applications.

When a low-pressure conveyor is used to deliver the coating material at low pressure to a low-pressure spray gun and use it to coat the workpiece, this is referred to as a low-pressure application. In the low-pressure application, the pressure generated with the help of a low-pressure conveyor is between 0.5 bar and 8 bar. The pressure is provided by a suitable pump or by a pressure vessel.

If, on the other hand, the coating material is conveyed under high pressure to a high-pressure spray gun with a high-pressure conveyor and the workpiece is then coated with it, this is referred to as a high-pressure application. In high-pressure applications, the pressure generated by a high-pressure conveyor is between 50 bar and 500 bars. Suitable pumps serve as high-pressure conveyors.

State of the art

In principle, high-pressure conveyors are known. For example, from the user manual "Cobra 40-10 Cobra 40-25 high pressure double diaphragm pumps", issue 01/2018 of the company J. Wagner GmbH two high-pressure conveyors are known that can generate a pressure of 250 bar. The structure of this high-pressure double diaphragm pump is in the Figures 12 and 13 shown. This high-pressure conveyor and not only this, but all high-pressure conveyors must be connected by appropriately pressure-resistant pipes or hoses for safety reasons. As a result, they are inherently more robust than low-pressure conveyors, which means they are heavier, use more materials and produce more expensively than a low-pressure design.

The low-pressure application has the advantage over the high-pressure application that the coating quality is higher and particularly thin layers can be achieved. However, the low-pressure application has the disadvantage that it generates more overspray and the coating process takes longer than with the high-pressure application.

In particular, if many different workpieces are to be coated and/or the workpiece sizes vary frequently and/or there are frequently changing requirements for the surface quality, it may be necessary for the user to have both a low-pressure and a a high-pressure application is available. The purchase of two coating systems, one for the low-pressure application and one for the high-pressure application, is expensive, however.

Presentation of the invention

One object of the invention is to specify a coating installation for coating workpieces with coating material, which is suitable for being able to operate both a low-pressure coating applicator and a high-pressure coating applicator with it.

Advantageously, with the coating system according to the invention, the safety of the operating personnel is guaranteed at all times.

The object is achieved by a coating system for coating workpieces with coating material having the features specified in patent claim 1.

The coating system according to the invention for coating workpieces with coating material comprises a low-pressure material conveyor in order to convey the coating material from a storage container at low pressure. The system also includes a high-pressure material applicator and a high-pressure material conveyor 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, the distributor inlet with the first distributor outlet and the second distributor outlet can be connected. The distributor inlet can be charged with the coating material coming from the low-pressure material conveyor. The high-pressure material conveyor can be supplied with coating material via the first distributor outlet. The system also includes a low pressure material applicator which is supplyable with coating material via the second manifold outlet.

Advantageous developments of the invention result from the features specified in the dependent patent claims.

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 charged with the coating material coming from the further low-pressure material conveyor.

In a possible further development of the embodiment just mentioned, the coating material originating from the low-pressure material conveyor is applied in addition to the coating material originating from the further low-pressure material conveyor. This is particularly advantageous for multi-component paints because the different components of the paint are brought together in this way. For example, paint (1st component of the coating material), which comes from the low-pressure material conveyor, and hardener (2nd component of the coating material), which comes from the other low-pressure material conveyor, can be brought together.

It is also possible that a third component is added in the low-pressure part of the system. This component can be, for example, an additional reactant or diluent material. The diluent material or, in short, the diluent is used to change the viscosity of the material being pumped.

In another possible development of the embodiment just mentioned, the coating material coming from the low-pressure material conveyor is applied as an alternative to the coating material coming from the further low-pressure material conveyor. This is advantageous if the low-pressure material conveyor conveys a first color (coating material 1) and the other low-pressure material conveyor conveys a second color (coating material 2) that differs from the first color. In this further development, the different colors are transported separately from one another to the distributor inlet.

In a further embodiment of the coating system according to the invention, a mixer is provided which is connected between the low-pressure material conveyor and the distributor. This is particularly advantageous for multi-component paints because it allows the material components of the paint coming from the low-pressure material conveyors to be brought together and mixed in the low-pressure section of the coating system.

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

In a development of the coating system according to the invention, the low-pressure material conveyor has a double diaphragm pump. The advantage of the double diaphragm pump is that it conveys the material with very little shear and is therefore stress-free. Another advantage of the double diaphragm pump is that it is hermetically sealed - due to its design - so that no molecules from the outside can get into the delivery tract of the pump.

In another development of the coating system according to the invention, the low-pressure material conveyor has a gear pump. With the gear pump, the amount of material to be conveyed can be specified very precisely. In addition, a particularly constant flow of material can be achieved with the gear pump. Both factors are beneficial for a good coating result.

An additional gear pump could also advantageously be provided, for example in the low-pressure path after the distributor, in order to additionally improve the coating process.

In another embodiment of the coating system according to the invention, the low-pressure material conveyor has a pressure vessel. The pressure in the pressure vessel can be built up with a pump. The pressure tank has the advantage that the material pressure it makes available has less pulsation than the pressure generated by a pump.

The high-pressure material conveyor in the coating system according to the invention is preferably designed and operable in such a way that it generates a pressure of more than 50 bar.

In a development of the coating system according to the invention, the high-pressure material conveyor is designed as a piston pump or as a piston double-diaphragm pump. The double-diaphragm piston pump is also known as a high-pressure double-diaphragm pump and offers even greater safety than the piston pump, as it acts like a non-return valve due to its design. With the piston double diaphragm pump, higher pressures can be generated than with the piston pump without jeopardizing operational safety.

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

As an alternative to this, the distributor in the coating system according to the invention can have an actuator in order to connect the supply input either to the first output or to the second output.

In one embodiment of the coating system according to the invention, the distributor has a shuttle valve.

As an alternative to this, the distributor in the coating system according to the invention can have a ball valve.

In addition, in the coating system according to the invention, it can be provided that the distributor is designed in this way is that it is flushable. For this purpose it can be provided that the distributor is designed without dead space or at least essentially free of dead space. In addition, flushability can be improved if the distributor has smooth surfaces in the material-carrying area. Furthermore, it is advantageous if the distributor is made of an inert material, such as stainless steel or polytetrafluoroethylene (PTFE). In addition, the distributor can be flushed or cleaned even more easily if it is designed in such a way that it does not require packing, ie seals.

In the coating system according to the invention, a high-pressure line can be provided, via which the coating material reaches the high-pressure material conveyor from the distributor. As a result, operational reliability can be further increased. If the high pressure conveyor fails to route the high pressure upstream instead of downstream, the risk of the line bursting is further reduced.

In one embodiment of the coating system, a low-pressure supply line is provided in order to supply the distributor with coating material on the inlet side. 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 kept in the low-pressure range and only transformed to high pressure when the high pressure is actually required.

In order to achieve the object, it is also proposed that in the coating system according to the invention a non-return valve is provided at the downstream end of that supply line which connects the high-pressure conveyor to the distributor.

In addition, 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.

It is also possible that, in the coating system according to the invention, two non-return valves connected in series are provided on the inlet side of the high-pressure material conveyor. This offers the advantage of increased security through redundancy. This means that the particularly high legal requirements for ensuring operational safety that apply in some regions of the world can be satisfied.

In the coating system according to the invention, it can be provided that a bursting disc is provided in the material-carrying low-pressure area. If the bursting disc ruptures, the operator is immediately notified that there is a fault in the high-pressure section. This also serves to increase the operational reliability of the coating system.

The coating system advantageously has wheels so that the system can be moved. This means that the system can be used at different locations.

In addition, a coating system with the coating installation described above is proposed, in which a robot is provided for manipulating the low-pressure material applicator and/or the high-pressure material applicator. This further increases the degree of automation.

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 can be adjusted.

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

In addition, a low-pressure supply line can be provided in the coating system according to the invention in order to supply the distributor with coating material on the inlet side. Advantageously, the low-pressure supply line does not need to be dimensioned as robustly as a high-pressure line.

The line via which the coating material gets from the distributor to the low-pressure applicator can also be designed as a low-pressure line.

Advantageously, the coating system has a controller to control the distributor and/or the mixer and/or the material conveyor.

In the coating system according to the invention, the low-pressure material applicator and/or the high-pressure material applicator can, for example, be on a robot, a be mounted on a lifting device or a single or multi-axis moving device. The same applies to the distributor.

Brief description of the drawings

Figur 1

zeigt in Form eines Blockschaltbilds eine erste mögliche Ausführungsform der erfindungsgemässen Beschichtungsanlage zum Beschichten von Werkstücken mit Beschichtungsmaterial.

Figur 2

zeigt in Form eines Blockschaltbilds eine zweite mögliche Ausführungsform der erfindungsgemässen Beschichtungsanlage.

Figur 3

zeigt in Form eines Blockschaltbilds eine dritte mögliche Ausführungsform der erfindungsgemässen Beschichtungsanlage.

Figur 4

zeigt in Form eines Blockschaltbilds eine vierte mögliche Ausführungsform der erfindungsgemässen Beschichtungsanlage.

Figur 5

zeigt in Form eines Blockschaltbilds eine fünfte mögliche Ausführungsform der erfindungsgemässen Beschichtungsanlage.

Figur 6

zeigt in Form eines Blockschaltbilds eine erste mögliche Ausführungsform eines Hochdruck-Materialförderers.

Figur 7

zeigt in Form eines Blockschaltbilds eine zweite mögliche Ausführungsform eines Hochdruck-Materialförderers.

Figur 8

zeigt eine mögliche Ausführungsform der erfindungsgemässen Beschichtungsanlage in einer dreidimensionalen Ansicht.

Figur 9

zeigt die Ausführungsform gemäss Figur 8 der erfindungsgemässen Beschichtungsanlage in der Seitenansicht.

Figur 10

zeigt eine mögliche Ausführungsform eines Druckbehälters in der Seitenansicht.

Figur 11

zeigt den Druckbehälters in einer dreidimensionalen Ansicht.

Figur 12

zeigt eine mögliche Ausführungsform eines Hochdruck-Materialförderers in der Seitenansicht teilweise im Schnitt.

Figur 13

zeigt die Farbstufe des Hochdruck-Materialförderers im Schnitt.

Figur 14

zeigt eine mögliche Ausführungsform eines Wechselventils in einer dreidimensionalen Ansicht.

Figur 15

zeigt die Ausführungsform des Wechselventils in der Ansicht von vorn.

Figur 16

zeigt das Wechselventil im Längsschnitt.

Figur 17

zeigt das Wechselventil im Querschnitt.

The invention is explained in more detail below with several exemplary embodiments with reference to 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 a second possible embodiment of the coating system according to the invention in the form of a block diagram.

figure 3

shows a third possible embodiment of the coating system according to the invention in the form of a block diagram.

figure 4

shows a fourth possible embodiment of the coating system according to the invention in the form of a block diagram.

figure 5

shows a fifth possible embodiment of the coating system according to the invention in the form of a block diagram.

figure 6

shows a first possible embodiment of a high-pressure material conveyor in the form of a block diagram.

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 FIG figure 8 the coating system according to the invention in side view.

figure 10

shows a possible embodiment of a pressure vessel in side view.

figure 11

shows the pressure vessel in a three-dimensional view.

figure 12

shows a possible embodiment of a high-pressure material conveyor in a side view, partially in section.

figure 13

shows the paint level of the high-pressure material feeder in section.

figure 14

shows a possible embodiment of a shuttle valve in a three-dimensional view.

figure 15

shows the embodiment of the shuttle valve in front view.

figure 16

shows the shuttle valve in longitudinal section.

figure 17

shows the shuttle valve in cross section.

Ways to carry out the invention

A first possible embodiment of the coating system according to the invention for coating workpieces with coating material is figure 1 shown. The coating system is also referred to as a system for short. It comprises a low-pressure material conveyor 1 in order to convey the coating material 31 from a storage container 21 via a line 61 . Thereafter, with the aid of the low-pressure conveyor 1 , the coating material 31 is fed at low pressure via a line 71 to a material feed device 10 . The reservoir 21, the line 61, the low-pressure material conveyor 1, and the line 71 are also referred to below as the first low-pressure ink stage.

In addition to the first low-pressure color stage, the coating system includes three further low-pressure color stages. The second low-pressure ink stage comprises a reservoir 22, a line 62, a low-pressure conveyor 2 and a line 72. The third low-pressure ink stage comprises a reservoir 23, a line 63, a low-pressure conveyor 3 and a line 73. Finally, the fourth low-pressure ink stage comprises a reservoir 24, a Line 64, a low-pressure conveyor 4 and a line 74. The four low-pressure color stages can be constructed in the same way. But this is not mandatory.

Each of the low pressure color stages may be for a different coating material or component of the coating material. For example, the first low-pressure color stage can be provided for a first color and the second low-pressure color stage can be provided for a second color that differs from the first color. The third color stage can be provided for a component of the color, for example the hardener. The fourth color level can serve as a reserve. It is therefore not necessary for all four color levels to be used at the same time.

As in figure 1 shown, the downstream ends of the lines 71, 72, 73 and 74 lead to the material feed device 10. The material feed device 10 is controlled by a higher-level controller 40 and can specify, for example via valves, which of the materials 31 to 34 is fed into the line 81. Provision can also be made for the time period or the amount or the amount ratio to be specified by the controller 40 . The material feed device 10 then opens and then closes the valves in the lines 71 to 74 accordingly figure 3 2 shows an example of how corresponding valves 17 and 19 are arranged for two color stages in order to control the flow of material in the two lines 71 and 72.

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 there to its inlet 11.1. If necessary, it can be provided that the Distributor 11 can be controlled via the controller 40. The distributor 11 has in accordance with the execution figure 1 two outlets 11.2 and 11.3, which can be connected to the inlet 11.1. The distributor 11 can also have further outlets (not shown in the figures), which can be connected to the inlet 11.1.

One outlet 11.3 is connected to a low-pressure material applicator 14 via a line 92. The other outlet 11.2 is connected to a high-pressure material conveyor 12 via a line 91. This 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 .

The distributor 11 serves to direct the coating material 31 coming 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 designed differently. Various embodiments of the manifold 11 are discussed below.

A spray device is referred to here as a low-pressure coating applicator, low-pressure material applicator or low-pressure spray applicator, which is intended for operation in the low-pressure range (between 0.5 bar and 8 bar) and with which the coating material can be sprayed onto the workpiece to be coated. The low-pressure coating applicator can be a manual or automatic spray device. The manual spray device is also referred to as a spray gun.

A high-pressure coating applicator, high-pressure material applicator or high-pressure spray applicator is a spraying device that is intended for operation in the high-pressure range (between 50 bar and 500 bar) and with which coating material can be sprayed onto the workpiece to be coated. Like the low-pressure coating applicator, the high-pressure coating applicator can be designed as a manual or automatic spray device.

In principle, coating applicators can be used, which atomize the material, for example, using air and/or hydraulic material pressure. If required, the coating applicators can also be equipped with an electrostatic unit to charge the coating material electrostatically. This will attract the coating material to the workpiece, which is grounded or at a lower electrical potential.

Wet paint is preferably used as the coating material. This can be one-component wet paint or multi-component wet paint. The term coating material is to be understood here in such a way that it can stand for both the ready-to-use wet paint and for a component of the paint, such as the paint or the hardener. So when we talk about coating material below, it depends on the context whether a material component of a multi-component paint or the ready-to-use multi-component paint is meant.

2nd embodiment

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

In this embodiment, the distributor 11 comprises a T-piece 11.6. The inlet of the tee 11.6 is the manifold inlet 11.1, the first outlet of the tee 11.6 is the outlet 11.2 and the second outlet of the tee 11.6 is the outlet 11.3 of the manifold 11. By the term tee is meant that the inlet 11.1 is connected without interruption via a connecting channel with both outlets 11.2 and 11.3. The course of the connecting channel can be T-shaped or Y-shaped, for example.

The coating system designed in this way is suitable for being able to coat the workpieces simultaneously with the low-pressure coating applicator 14 and with the high-pressure coating applicator 13 if required. Since each of the coating applicators 13, 14 has a trigger guard in this embodiment, the personnel can choose which of the two coating applicators 13, 14 is to be used to coat the workpiece.

In this embodiment of the coating system, it is not provided that one of the two or both lines 91 and 92 are depressurized with the distributor 11 . If the two lines 91 and 92 are depressurized are switched, this is done by the low-pressure conveyor 1 is switched off.

3rd embodiment

A third possible embodiment of the coating system according to the invention is figure 3 shown in the form of a block diagram.

In this embodiment, the distributor 11 comprises an actuator 11.5 which can be controlled via the controller 40. The actuator 11.5 can be designed in such a way that it acts as a changeover switch. It is thus possible to supply coating material to either the low-pressure coating applicator 14 or the high-pressure coating applicator 13 .

When the actuator connects the manifold inlet 11.1 to the outlet 11.3 (switch position 1), the low-pressure coating applicator 14 is operational, while the high-pressure section (high-pressure conveyor 12, line 93 and high-pressure coating applicator 13) is completely switched off. 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.

When the actuator connects the manifold inlet 11.1 to the outlet 11.2 (switch position 2), the high-pressure coating applicator 13 is operational, but 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 separated from the line 92 without endangering the operating personnel. In addition, the low-pressure coating applicator 14 can be cleaned in this operating state, for example.

The actuator 11.5 can also be designed in such a way that more than two switching positions are possible. For example, in the embodiment of the actuator 11.5 according to figure 5 four switching positions selectable.

In the supply line 81, at the downstream end, as in figure 3 indicated, a check valve 100 may be arranged.

4th embodiment

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

In this embodiment, it is possible to supply coating material only to the low-pressure coating applicator 14 and to depressurize the high-pressure portion. 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.

When the 2/2-way valve 211 is in the first position 211.1 (as in 4 shown), it connects the manifold inlet 11.1 to the outlet 11.3. Now the coating material is fed to the low-pressure coating applicator 14, the coating applicator 14 is ready for operation. The high-pressure section (high-pressure conveyor 12, line 93 and high-pressure coating applicator 13), on the other hand, is completely pressure-free.

On the other hand, if 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 now fed to the high-pressure conveyor 12 and via this to the high-pressure coating applicator 13 . The coating applicator 13 is ready to be used to coat workpieces. The line 92 and the low-pressure coating applicator 14, on the other hand, are completely depressurized.

The coating system can, as in figure 4 shown, also have a mixer 15 . This is connected between the material feed device 10 and the distributor 11 . The inlet of the mixer 15 is preferably 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 particularly advantageous when changing colors.

The lines 71 and 72 can be more or less long as required. If larger distances between the low-pressure material conveyor 1, 2 and the distributor 11 are to be bridged, this is preferably not done with the aid the line 81, but accomplished with the lines 71 and 72. In figure 4 is this implied. This ensures, among other things, that there is little material that has already been mixed in the line 81 and consequently only a small amount of the material that has already been mixed has to be flushed out of the line 81 during flushing.

A further advantage of this embodiment is that the number of components that can come into contact with already mixed 2K material is minimized. As a result, detergent consumption during rinsing processes can be significantly reduced.

Next is in figure 4 an optional flushing agent connection 18 is shown. The detergent connection 18 can be connected via an in figure 4 not shown detergent reservoir are supplied with detergent. With the valve 16 open, the coating system can be cleaned or flushed. For example, via the flushing agent connection 18, flushing agent can be routed 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 to be pumped.

This in figure 4 Instead of the 2/2-way valve, the actuator shown can also be designed in such a way that up to four switching positions are possible. For this purpose, the actuator can have two 2/2-way valves, which can each be activated by the controller 40 via a control line, so that a total of four switching positions are possible. 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 switch position both lines are open and in the fourth switch position both lines are closed.

Instead, the actuator can also have a 3/2-way valve. The actuator can then enable the following three switch positions, for example: low-pressure line open and high-pressure line closed; low pressure line closed and high pressure line open; both lines open.

5th embodiment

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

If the valve 311 is in the first position 311.1 (as in figure 5 shown), the line 91 is connected to the 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 the line 93. The high-pressure coating applicator 13 can now be used for coating. Line 92 and low pressure coating applicator 14 are depressurized.

When the valve 311 is in the second position 311.2, both the low-pressure coating applicator 14 and the high-pressure conveyor 12 are supplied with coating material. It can now be coated with the low-pressure coating applicator 14 and the high-pressure coating applicator 13 at the same time. In the position 311.2, the valve 311 corresponds functionally to the T-piece 11.6 figure 2 .

As in the fourth embodiment according to figure 4 it is also possible in the fifth embodiment to supply only the low-pressure coating applicator 14 with coating material and to completely depressurize the section working with high pressure. 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.

Furthermore, with the fourth position 311.4 of the valve 311 it can be achieved that neither the low-pressure coating applicator 14 nor the high-pressure section is pressurized.

Also at the in figure 5 embodiment shown may be in the supply line 81 at the downstream end, as in FIG figure 3 indicated, a check valve 100 may be arranged.

1. Embodiment of the high-pressure material conveyor

figure 6 shows a first possible embodiment of the high-pressure material conveyor 12 in the form of a block diagram. The block diagram shows the structure of a piston double diaphragm pump 50 in simplified form. The piston double diaphragm pump 50 has two inlet valves 51 and 52, a cylinder 53, a piston 54 which is movably arranged in the cylinder 53, two diaphragms 55.1, 55.2 and two outlet valves 57, 58. The piston 54 is connected via a piston rod to and driven by a motor 56, for example an air motor. The piston 54 acts on the two membranes 55.1 and 55.2. The membrane 55.1 forms an upper pump chamber 59.1 with the housing and the membrane 55.2 forms a lower pump 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 themselves.

Coating material is supplied at low pressure to the piston double-diaphragm pump 50 via the supply line 91 . When the piston 54 moves down in the cylinder 53, the first membrane 55.1 is pulled down, the upper pump chamber 59.1 is enlarged and coating material is sucked into the upper pump chamber 59.1 via the inlet valve 51. At the same time, during the downward movement of the piston 54, the second membrane 55.2 is pressed down, the lower pump chamber 59.2 is reduced in size and the coating material located therein is pressed into the line 93 via the outlet valve 58. In this case, the inlet valve 52 is closed. When the piston 54 moves upwards again after having passed the bottom reversal point, the inlet valve 51 and over closes the inlet valve 52, which is now open, coating material is sucked into the now enlarging lower pump chamber 59.2. The outlet 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 pressed into the line 93 via the outlet valve 57, which is now open.

If the inlet valve 51 is permanently open in the piston double diaphragm pump due to a defect, the coating material is pumped under pressure into the common delivery channel 91 in the working cycle of the upper pump chamber 59.1. The pressurized material is actively sucked into the lower, pressure-resistant pump chamber 59.2 by the force-driven and simultaneous suction cycle of the lower pump chamber 59.2. This effectively prevents an impermissible pressure load on upstream components, such as the line 91 and the distributor 11 (not shown in FIG. 6).

The same applies analogously if the inlet valve 52 is permanently open due to a defect.

A check valve 150 can be provided in the area of the pump inlet 50.1, which forms the common suction channel of the double-diaphragm piston pump 50. Because of the two check inlet valves 51 and 52 which are arranged in the same direction and open alternately, the additional, redundant check valve 150 is not absolutely necessary.

The same applies to other pumps if they have two check inlet valves arranged in the same direction and opening alternately on the inlet side, these inlet valves being connected to one another via a common intake duct (line 91 or delivery duct in the pump housing).

2nd embodiment of the high-pressure material conveyor

figure 7 shows a second 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-acting piston pump 110. During the downward movement of the working piston 114 driven by a drive piston 115, material previously sucked into the lower pump chamber 113.1 is conveyed into the upper pump chamber 113.2 via the overflow channel 114.1 via the open check overflow valve 117 with the non-return inlet valve 112 being positively closed. From this, the material is conveyed to the pump outlet and thus into the line 93 during the next upward movement of the working piston 114 .

In the following it is assumed that the check inlet valve 112 is permanently open due to a defect. During the downward movement of the working piston 114, material previously sucked into the lower pump chamber 113.1 is transported at least partially through the intake channel 119 via the open non-return inlet valve 112 at high pressure. A second, redundant check valve 111 is arranged in the intake passage 119, 91 in order to avoid impermissible pressure loading of upstream components. This prevents that material under high pressure flows back into line 91.

It is therefore advantageous to provide non-return valves which ensure redundancy in the event of a defect. These non-return valves can work in parallel and in opposite directions, as in the case of the double-diaphragm piston pump in figure 6 shown. However, the check valves can also work sequentially and in the same direction, as in the case of the piston pump according to FIG figure 7 .

figure 8 shows a possible embodiment of the coating system in a three-dimensional view. In figure 9 the coating system is shown in a side view. The coating system comprises a frame 540 arranged on wheels 550. The frame 540 is designed in such a way that it can be variably equipped. At the in figure 8 In the variant shown, six identical low-pressure conveyors 501 to 506 and one high-pressure conveyor 400 are installed. If necessary, however, the frame 540 can also be equipped with one less low-pressure conveyor and an additional high-pressure conveyor instead. It is also easily possible to mount various low-pressure conveyors on the frame 540. In the lower area, the frame 540 has a floor designed as a grating. Various storage containers 21, 22, 23 can be placed on it, for example. It is also possible to use a pressure vessel 410 (see Figures 10 and 11 ) to be placed on the rack 540 (in figure 8 Not shown). For example, the pressure vessel 410 can be used in place of one of the low pressure conveyors 501-506 to convey the material. The controller 40 can be arranged laterally next to the frame 540 . she can, as in figure 8 shown, be arranged on a separate, mobile frame 560. This allows the operating personnel to position the controller 40 independently of the frame 540 in the best possible way.

In figure 10 is a possible embodiment of the pressure vessel 410 in side view and in figure 11 presented in a three-dimensional view. The pressure tank 410 is used to convey the material and can replace a low-pressure pump. With the pressure tank 410, the material can be conveyed without pulsation and with low shear.

The high-pressure material conveyor 12 can be a high-pressure double-diaphragm pump, for example. A possible embodiment of such a high-pressure double diaphragm pump 50 is figure 12 shown partially in section in the side view. This is a high-pressure double-diaphragm pump, such as that marketed by J. Wagner GmbH under the product name "Cobra".

The paint stage 403 of the high-pressure double diaphragm pump 50 is in figure 13 shown in section. The paint stage 403 of the high-pressure double diaphragm pump 50 is the part of the pump into which the paint is sucked and from which the paint that is under high pressure is pushed out again. The paint stage 403 is therefore that part of the pump which comes into contact with paint and which has to be cleaned when changing the paint.

The high-pressure double diaphragm pump 50 has a pump inlet 50.1 for connection to line 91 (in the figure not shown) on. The coating material reaches a first inlet valve 51 and a second inlet valve 52 from the pump inlet 50.1. The other part of the material passes through the inlet valve 52 into the second pump chamber, the volume of which can be changed using a second membrane 402 . The two diaphragms 401 and 402 are moved synchronously via 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.

The functional principle of the high-pressure double diaphragm pump 50 is shown in the block diagram in figure 6 shown and has already been described above at the appropriate point. To avoid repetition, on figure 6 and the associated description.

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

In the case of the coating system according to the invention, it is advantageous to design the long material-carrying lines and, if there is a color change and a mixing system, these too as a low-pressure system. The transformation to high pressures advantageously takes place just before the high-pressure coating applicator(s) 13 with the aid of the interposed high-pressure conveyor 12.

Piston membrane pumps are particularly suitable as high-pressure conveyors 12 . They only exert extremely low shearing forces on the coating material, are hermetically sealed from the environment, generate only low pulsation and suck in the coating material evenly.

If a piston membrane pump is only used for the high-pressure conveyor 12, the consumption of detergent for cleaning the coating system increases only slightly. The reason for this is the usually very small pump chamber volume of piston diaphragm pumps.

Diaphragm pumps are suitable as low-pressure conveyors. Designing the low-pressure conveyors as diaphragm pumps has the advantage that the coating system can be rinsed easily and with little solvent and can therefore be cleaned.

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

The high-pressure piston pump according to figure 7 can be designed in such a way that it can also convey highly viscous material with a high solids content. Diaphragm pumps are typically less suitable for this.

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

The piston pump 110 can be designed with a high transmission ratio and can then generate high pressures. This variant of the piston pump 110 is also referred to as a high-pressure piston pump. If the piston pump 110 is designed with a low transmission ratio (low-pressure piston pump), it generates a lower pressure than the high-pressure piston pump, but has a higher suction capacity than the latter. As a rule, the piston pump 110 is not hermetically sealed and causes a higher material shear than the piston diaphragm pump 50.

The foregoing description of the embodiments according to the present invention is for illustrative purposes only. Various changes and modifications are possible within the scope of the invention. For example, the various in the Figures 1 to 14 components of the coating system shown can also be combined with one another in a manner other than that shown in the figures. For example, one of the figures 2 , 3 , 4 and 5 shown embodiments of the distributor 11 also in accordance with the coating system figure 1 come into use.

One of the two or both applicators 13 and 14 and possibly also the distributor 11 can be used on a robot, a lifting device or a single or multi-axis movement device (not shown in the figures).

Reference List

1

Low pressure material conveyor

2

Low pressure material conveyor

3

Low pressure material conveyor

4

Low pressure material conveyor

10

material feeding device

11

distributor

11.1

manifold inlet

11.2

manifold outlet

11.3

manifold outlet

11.5

actuator

11.6

tee

12

High Pressure Material Conveyor

13

High Pressure Material Applicator

14

Low Pressure Fluid Applicator

15

mixer

16

Valve

17

Valve

18

detergent connection

19

Valve

21

reservoir

22

reservoir

23

reservoir

24

reservoir

31

coating material

32

coating material

33

coating material

34

coating material

40

steering

50

Piston double diaphragm pump (high pressure double diaphragm pump)

50.1

pump inlet

51

intake valve

52

intake valve

53

cylinder

54

Pistons

55.1

first membrane

55.2

second membrane

56

engine

57

outlet valve

58

outlet valve

59.1

pump chamber

59.2

pump chamber

61

management

62

management

63

management

64

management

71

management

72

management

73

management

74

management

81

supply line

91

management

92

management

93

management

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

Pistons

114.1

overflow channel

115

cylinder

116

engine

117

check valve

119

intake duct

150

check valve

211

2/2 way valve

211.1

first valve position

211.2

second valve position

311

4-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

membrane

402

membrane

403

color level

403.1

exhaust port

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

shuttle valve

601

valve needle

602

valve needle

603

channel

Claims (21)

Coating system for coating workpieces with coating material, - in 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 which a high-pressure material applicator (13) and a high-pressure material conveyor (12) are provided for conveying the coating material (31) at high pressure to the high-pressure material applicator (13), - in which a distributor (11) is provided which has a distributor inlet (11.1) and a first and a second distributor outlet (11.2; 11.3), the distributor inlet (11.1) being connected to the first distributor outlet (11.2) and the second distributor outlet (11.3 ) is connectable, - in which the distributor inlet (11.1) can be acted upon by the coating material (31) coming from the low-pressure material conveyor (1), - in which the high-pressure material conveyor (12) can be supplied with coating material via the first distributor outlet (11.2), and - In which a low-pressure material applicator (14) is provided, which can be supplied with coating material via the second distributor outlet (11.3). Coating system according to claim 1, - in which a further low-pressure material conveyor (2) is provided, - in which the distributor inlet (11.1) can be acted upon by the coating material (31) coming from the further low-pressure material conveyor (2). Coating system according to claim 2,
in which a mixer (15) is provided, which is connected between the low-pressure material conveyors (1; 2) and the distributor (11). Coating plant according to one of patent claims 1 to 3,
wherein the low pressure material conveyor (1) is constructed and operable to generate a pressure of less than 32 bar and preferably less than 20 bar. Coating system according to one of the preceding claims,
in which the low-pressure material conveyor (1) is designed as a double diaphragm pump (400). Coating plant according to one of patent claims 1 to 4,
in which the low-pressure material conveyor (1) has a gear pump. Coating system according to one of the preceding claims,
in which the low-pressure material conveyor (1) has a pressure vessel (410). Coating plant according to one of patent claims 1 to 3,
in which the high-pressure material conveyor (12) is designed and operable in such a way that it generates a pressure of more than 50 bar. Coating system according to one of the preceding claims,
in which the high-pressure material conveyor (12) is designed as a piston pump or as a piston double-diaphragm pump. Coating system according to one of the preceding claims,
in which the distributor (11) has a T-piece (11.6). Coating plant according to one of patent claims 1 to 8,
in which the distributor (11) has an actuator (11.5) in order to connect the supply input (11.1) either to the first output (11.2) or to the second output (11.3). Coating plant according to one of patent claims 1 to 8,
in which the distributor (11) has a shuttle valve (211). Coating plant according to one of patent claims 1 to 8,
wherein the distributor (11) has a ball valve (311). Coating system according to one of the preceding claims,
in which a high-pressure line (91) is provided, via which the coating material passes from the distributor (11) to the high-pressure material conveyor (12). Coating system according to patent claim 14, - in which a low-pressure supply line (81) is provided in order to supply the distributor (11) with coating material on the inlet side, - In which the low-pressure supply line (81) is longer than the high-pressure line (91). Coating system according to patent claim 15,
wherein a check valve (100) is provided at the downstream end of the supply line (81). Coating plant according to one of patent claims 15 or 16,
wherein a check valve (51, 52; 61) is provided at the downstream end of the high-pressure line (91). Coating system according to one of claims 15 to 17,
in which two check valves (61; 62) connected in series are provided on the inlet side of the high-pressure material conveyor (12). Coating plant according to one of patent claims 16 to 18,
in which the check valve (100) has a bursting disk. Coating system according to one of the preceding claims,
in which wheels (550) are provided for moving the coating system. Coating system with a coating installation according to one of Patent Claims 1 to 20,
in which a robot is provided for manipulating the low-pressure material applicator (14) and/or the high-pressure material applicator (13).

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