Dense-phase powder pump for conveying coating powder

Abstract

The invention relates to a dense-phase powder pump (20) for conveying coating powder, wherein the dense-phase powder pump (20) is designed to suck up, via a powder inlet of the dense-phase powder pump (20), either coating powder from a powder chamber of a first powder container or coating powder from a powder chamber of a second powder container and to supply, via a powder outlet (25) of the dense-phase powder pump (20), the sucked-up coating powder to a powder discharge device or to a powder reservoir, wherein a powder switch (1) is provided at the powder inlet of the dense-phase powder pump (20) or wherein the powder inlet of the dense-phase powder pump (20) is designed as a powder switch (1), the powder switch (1) being designed to connect the powder inlet of the dense-phase powder pump (20) in terms of flow either to a first powder line / channel system leading into the powder chamber of the first powder container or to a second powder line / channel system leading into the powder chamber of the second powder container.

Description

[0001] POWDER DENSITY PUMP FOR TRANSPORTING COATING POWDER

[0002] Description

[0003] The present invention relates generally to dense phase powder pumps for conveying coating powder.

[0004] Dense-phase powder pumps of the type considered here have at least one conveying chamber equipped with a powder inlet valve and a powder outlet valve. The conveying chamber can be connected alternatively to a vacuum source during a suction phase or to a transport compressed air source during a discharge phase. Using the vacuum from the vacuum source, powder is sucked into the conveying chamber through the open powder inlet valve while the powder outlet valve is closed. Using the transport compressed air from the transport compressed air source, the powder in the conveying chamber is discharged through the open powder outlet valve while the powder inlet valve is closed.

[0005] Dense phase powder pumps can have several conveying chambers arranged parallel to one another, which operate in phases such that coating powder is alternately sucked into one conveying chamber while coating powder is discharged from the other conveying chamber.

[0006] For example, EP 1 551 558 A1 relates to a dense phase powder pump comprising a first powder feed chamber and a second powder feed chamber arranged parallel to the first powder feed chamber. The two powder feed chambers of the dense phase powder pump known from this prior art are each delimited on both the intake and discharge sides by a mechanically actuated pinch valve arrangement.

[0007] In detail, it is provided that in the suction-side or delivery-side area of ​​the dense phase powder pump, the powder hoses connected to the respective powder delivery chambers of the dense phase powder pump can be deformed with a mechanically operated stamp in order to squeeze or open the hose section if necessary.

[0008] Each powder feed chamber of the dense phase powder pump known from this prior art is assigned a filter tube which delimits the circumference of the corresponding powder feed chamber. The filter tube is permeable to air, but not to coating powder, and is surrounded by an annular chamber to which either negative pressure or compressed air can be connected. This allows coating powder to be alternately sucked into each powder feed chamber or expelled from the corresponding powder feed chamber using compressed air. The two powder feed chambers arranged parallel to each other are operated in alternating phases, which means that one of the two powder feed chambers sucks in coating powder through the powder inlet of the dense phase powder pump, while the other of the two powder feed chambers discharges a portion of coating powder previously sucked into the powder feed chamber via the powder outlet of the dense phase powder pump.

[0009] The use of dense phase powder pumps for conveying coating powder to corresponding devices for spraying coating powder, such as in particular powder spray coating guns, is known from the document DE 196 11 533 B4, the document WO 2004 / 087331 A1 and the document EP 1 566 352 A2.

[0010] Before the use of dense phase powder pumps of the type considered here became known for conveying coating powder, powder pumps designed as injectors were used, and these are still used today for conveying coating powder. In contrast to dense phase powder pumps, however, powder pumps designed as injectors (dilute phase powder pumps) have the disadvantage that powder pumps designed as injectors wear out relatively quickly and can typically convey a decreasing amount of coating powder per unit of time over time.

[0011] In this respect, dense phase powder pumps have become established in practice, particularly for applications where a constant amount of coating powder must be delivered per unit of time. The invention is based on the problem that powder coating systems and the associated powder supply devices must be carefully cleaned during a powder change (change from a first powder type to a second powder type), particularly during a color change (change from powder of a first color to a powder of a different color), since even a few powder particles of the previous powder type can result in coating defects when coating with the new powder type.

[0012] In particular, the prior art dense phase powder pumps for powder coating systems have the disadvantage that they cannot easily switch between different powder types or between fresh powder and recovery powder during a coating process, which has a negative impact on coating efficiency. For example, there is a desire to easily switch between fresh powder and recovery powder during an ongoing coating process. The fresh powder is typically applied to the surface areas of an object / workpiece to be coated that will form the visible side during later use, while recovery powder can be used for the remaining areas of the object / workpiece to be coated.A typical example is the coating of vehicle rims, where fresh powder is applied to the visible area of ​​the vehicle rim, i.e., the so-called A-side of the workpiece. In the case of vehicle rims, the visible area is therefore the outer visible surface.

[0013] The non-visible area of ​​the workpiece is the so-called B-side of the workpiece in its intended use, such as the rim well of a vehicle rim. Recovery powder can be used to coat the non-visible area of ​​the workpiece. A coating formed with recovery powder is certainly of inferior quality compared to one formed from virgin powder; however, this is irrelevant, since the coating formed with recovery powder is only present on the non-visible area of ​​the workpiece.

[0014] Accordingly, the object of the invention is to provide a dense phase powder pump for a powder coating system that enables the most efficient coating operation of the powder coating system. Furthermore, a method for changing the powder quickly and easily is to be provided.

[0015] This object is achieved by the subject matter of independent patent claim 1, wherein advantageous developments of the dense phase powder pump according to the invention are specified in the dependent claims.

[0016] Accordingly, the invention relates in particular to a dense phase powder pump for conveying coating powder, wherein the dense phase powder pump is designed to selectively suck in coating powder from the powder chamber of a first powder container or coating powder from the powder chamber of a second powder container via a powder inlet of the dense phase powder pump and to supply the sucked in coating powder to a powder dispensing device or a powder reservoir via a powder outlet of the dense phase powder pump.

[0017] Powder dispensing devices are, in particular, manual or automatic powder spraying devices. Automatic powder spraying devices are often attached to a stand, particularly a lifting stand, or a robot positioned outside a coating booth via a corresponding extension, with the extension extending through a (slotted) opening in a wall of the coating booth.

[0018] According to the invention, it is particularly provided that a powder switch is provided at the powder inlet of the powder pump, or that the powder inlet of the dense phase powder pump itself is designed as a powder switch.

[0019] The powder switch is designed to connect the powder inlet of the dense phase powder pump either to a first powder line / channel system opening into the powder chamber of the first powder container or to a second powder line / channel system opening into the powder chamber of the second powder container.

[0020] The advantages achievable with the solution according to the invention are obvious: by providing the powder switch, the dense phase powder pump can selectively draw coating powder from two different powder containers. Accordingly, during ongoing coating operations, powder dispensing devices (spray guns) can selectively be supplied with coating powder of different powder types or grades. Switching between different powder types or grades thus eliminates the need to clean the powder line / channel systems, since a separate powder line / channel system is preferably used for each powder type or grade to be sprayed.A powder line / channel system is available for each powder type, which can be connected to the powder outlet of the powder switch if required, in order to enable this coating powder to be supplied to the powder dispensing device, which is also connected to the powder outlet of the powder switch via the dense phase powder pump.

[0021] In particular, it is conceivable in this context that fresh powder is accommodated in the powder chamber of the first powder container and recovery powder is accommodated in the powder chamber of the second powder container.

[0022] On the other hand, it is of course also conceivable that different powder colors are present in the powder chambers of the first and second powder containers. It is also conceivable that both powder chambers contain coating powder of the same type / grade.

[0023] The term "recovery powder" as used herein refers to excess coating material or so-called "overspray material," i.e., coating material that could not be applied to the workpiece to be coated, or that has already been sprayed at least once during a coating process and has been recycled accordingly.

[0024] According to a preferred implementation of the dense-phase powder pump, the powder switch comprises a first powder inlet, which is fluidly connected or connectable to the first powder line / channel system, a second powder inlet, which is fluidly connected or connectable to the second powder line / channel system, and a powder outlet, which is fluidly connected to the powder inlet of the powder pump or, via a powder inlet valve, to a powder feed chamber of the dense-phase powder pump. Furthermore, a switching mechanism is used, which is designed to selectively fluidly connect the powder outlet either to the first powder inlet of the powder switch or to the second powder inlet of the powder switch.

[0025] This embodiment variant is characterized in particular in that the powder switch further comprises a purge air inlet, wherein the switching mechanism is designed such that the purge air inlet is fluidly connected to the second powder inlet when the powder outlet is fluidly connected to the first powder inlet.

[0026] Preferably, the switching mechanism is further designed such that the purge air inlet of the powder switch is fluidly connected to the first powder inlet of the powder switch when the powder outlet of the powder switch is fluidly connected to the second powder inlet of the powder switch.

[0027] In this way, the first and second powder inlets as well as the first powder line / channel system fluidly connected to the first powder inlet and the second powder line / channel system fluidly connected to the second powder inlet can be cleaned with purge air in an efficient manner without fundamentally interrupting the powder supply to the powder dispensing devices of the powder coating system.

[0028] According to a preferred implementation of the powder switch, the switching mechanism comprises a carriage assembly with a carriage that is adjustable and, in particular, linearly displaceable relative to a housing body of the powder switch. The first and second powder inlets of the powder switch are formed in the carriage, while the powder outlet of the powder switch is formed in the housing body of the powder switch. In particular, in this context, it is also provided that the purge air inlet of the powder switch is also formed in the housing body of the powder switch.

[0029] This design variant enables a particularly compact design of the powder switch. Preferably, the switching mechanism of the powder switch has a first drive associated with the carriage assembly, which is configured to move the carriage relative to the housing body of the powder switch as needed such that the powder outlet of the powder switch is fluidly connected either to the first powder inlet of the powder switch or to the second powder inlet of the powder switch.

[0030] Although it is fundamentally conceivable for the first drive to be designed as an electric motor-driven linear drive, for example, it is advisable to use a pneumatic drive for the first drive, which moves the carriage relative to the housing body of the powder switch by supplying compressed air. For this purpose, at least one pneumatic connection is assigned to the first drive, which is designed as a pneumatic drive.

[0031] The pneumatic actuator (primary actuator) can be based on the functional principle of a double-acting cylinder. Such a double-acting cylinder uses air force to move both when extending and retracting. In this design variant, the pneumatic actuator must be assigned a first pneumatic connection and a second pneumatic connection.

[0032] However, to achieve a particularly compact design for the powder diverter, it is preferred that the first drive, designed as a pneumatic drive, be based on the functional principle of a single-acting cylinder, so that only a single pneumatic connection is required for this design. Compressed air can enter through this single pneumatic connection and move the slide in one direction.

[0033] It is preferably provided that the carriage arrangement has a pretensioning element associated with the carriage, in particular in the form of a spring, which is designed to pretension the carriage into a first position in which the powder outlet of the powder switch is fluidly connected, for example, to the first powder inlet of the powder switch.

[0034] The pneumatic drive is designed to move the carriage, when compressed air is supplied via the (single) pneumatic connection of the powder switch, against the pretensioning force of the pretensioning element, which is designed in particular in the form of a spring, relative to the housing body of the powder switch from the first position to a second position in which the powder outlet of the powder switch is fluidly connected to the second powder inlet of the powder switch.

[0035] According to preferred implementations of the powder switch, it is provided that a channel system is formed in the housing body of the powder switch, which channel system is in fluid communication with the purge air inlet of the powder switch and has a first purge air outlet and a second purge air outlet, wherein the first and second purge air outlets are formed in an end face of the housing body of the powder switch that is adjacent to the carriage in such a way that the first purge air outlet is in fluid communication with the first powder inlet of the powder switch when the second powder inlet of the powder switch is in fluid communication with the powder outlet of the powder switch, and that the second purge air outlet is in fluid communication with the second powder inlet of the powder switch when the first powder inlet of the powder switch is in fluid communication with the powder outlet of the powder switch.

[0036] This is a particularly easy to implement but nevertheless effective solution, how the purge air inlet of the powder switch is automatically connected in terms of flow to the first powder inlet of the powder switch when the second powder inlet of the powder switch is fluidly connected to the powder outlet of the powder switch, or how the purge air inlet of the powder switch is automatically connected in terms of flow to the second powder inlet of the powder switch when the first powder inlet of the powder switch is fluidly connected to the powder outlet of the powder switch.

[0037] In addition, the integration of the channel system into the housing body of the powder switch enables a compact design of the powder switch.

[0038] In order to enable the carriage to be moved relative to the housing body of the powder switch with as little wear as possible, it is provided according to design variants of the powder switch that the carriage can be moved from a first position, in which there is a gap between the end face of the housing body of the powder switch that adjoins the carriage and the end face of the carriage that adjoins the housing body of the powder switch, relative to the housing body of the powder switch into a second position, in which the gap between the end face of the housing body of the powder switch that adjoins the carriage and the end face of the carriage that adjoins the housing body of the powder switch is eliminated or at least reduced.

[0039] In this context, it is conceivable for the carriage assembly to have a (second) drive configured to move the carriage relative to the housing body of the powder switch from the first position to the second position as needed. Preferably, the second drive is also designed as a pneumatic drive and has at least one corresponding pneumatic connection.

[0040] As with the first drive, it is advantageous, with regard to a particularly compact design of the powder switch, that the second drive, preferably designed as a pneumatic drive, is based on the functional principle of a single-acting cylinder, so that only a single pneumatic connection is required for the second drive. In this context, it is therefore advisable for the slide arrangement to have a preloading element associated with the slide, for example in the form of a spring or elastic element, which is designed to preload the slide relative to the housing body of the powder switch, in particular into the first position.

[0041] In order to enable particularly simple maintenance and, if necessary, cleaning of the powder switch, it is provided according to a further development of the powder switch that the first powder inlet and the second powder inlet are designed in a carrier and in particular in a carrier plate, wherein the carrier or the carrier plate together with the first and second powder inlets of the powder switch are received and in particular inserted in a receiving area of ​​the carriage and are held there preferably via a quick-release fastener.

[0042] According to a preferred implementation of the powder dense phase pump according to the invention, it has a modular structure.

[0043] The modular design of the dense phase powder pump according to the invention enables adjustments, optimizations, and even cost reductions to be made in individual modules of the dense phase powder pump without the typical "ripple effect" of changes occurring within the entire dense phase powder pump. The modularization of the dense phase powder pump according to the invention reduces product complexity and makes the customer order process more efficient by allowing the dense phase powder pump to be configured for the specific order instead of being designed specifically for the order.

[0044] In other words, the dense phase powder pump according to the invention is constructed according to a modular principle, whereby the functional components of the dense phase powder pump are divided into modules or assemblies.

[0045] The individual modules or assemblies of the powder dense phase pump, which is constructed according to the modular principle, can be joined together if the shape and function are suitable or integrated via appropriate interfaces.

[0046] The dense phase powder pump (according to the invention), constructed according to the modular principle and characterized by its modular design, enables the creation of individually configurable dense phase powder pumps without sacrificing economies of scale across series. The individual modules of the dense phase powder pump are, in particular, standardized building blocks that can be flexibly implemented using individual adaptation elements within the modular system.

[0047] The advantage of such a modular, dense phase powder pump is, on the one hand, increased flexibility in product and organizational development. Faster product cycles and greater adaptability are possible when various compatible dense phase powder pump modules are available, which can be attached, removed, replaced, or regrouped to ultimately adapt the dense phase powder pump to new conditions.

[0048] On the other hand, the modular design of the dense phase powder pump according to the invention provides the further advantage of enabling a wide product variety in a simple manner. Furthermore, more cost-effective production is possible due to identical series and simpler assembly processes. Finally, the modular design of the dense phase powder pump according to the invention also offers advantages with regard to the maintenance of the dense phase powder pump, as cost-effective repairs are possible by replacing defective components of the dense phase powder pump.

[0049] In particular, the dense phase powder pump according to the invention has a pump head module designed as a module, which has at least one powder conveying chamber which is or can be fluidly connected via the powder inlet optionally to the powder chamber of the first powder container or to the powder chamber of the second powder container and via a powder outlet to a powder reservoir or to a powder spray device.

[0050] In addition, the powder dense phase pump of this embodiment variant comprises a compressed air control module, which is also designed as a module and has a plurality of switching valves that are assigned to the individual, preferably modular, components of the pump head module and are designed to supply the pneumatically controllable components of the pump head module with compressed air or suction air or vacuum as required and in particular in a controlled manner.

[0051] Furthermore, a quick-change module can be used, which is arranged at least partially or regionally between the pump head module and the compressed air control module and is designed to detachably connect the pump head module to the compressed air control module, in particular in such a way that, when the pump head module is connected to the compressed air control module, the pneumatically controllable components of the pump head module are fluidly connected to the switching valves of the compressed air control module via the quick-change module.

[0052] By providing such a quick-change module, the pump head module can be separated from the compressed air control module of the dense phase powder pump in just a few simple steps, for example to replace or maintain components of the pump head module.

[0053] In particular, the quick-change module represents the interface between the pump head module and the compressed air control module. The quick-change module has, in particular, a quick-change mechanism via which the pump head module can be or is connected to the quick-change module in a detachable manner.

[0054] Preferably, the powder switch is also operatively connected to the compressed air control module via the quick-change module serving as an interface.

[0055] In particular, it is intended that the powder switch itself is designed as a module and can be assigned to the pump head module if required.

[0056] In other words, depending on the application, the pump head module can be connected to the powder switch designed as a module.

[0057] The quick-change module also represents the flow connection between the corresponding switching valves of the compressed air control module and the pneumatically controllable components of the powder switch module. In particular, the compressed air control module also serves to supply compressed air to the purge air inlet of the powder switch as required, to supply compressed air (or vacuum) to the pneumatic connection of the first drive of the powder switch as required, and / or to supply compressed air (or vacuum) to the pneumatic connection of the second drive as required.

[0058] An exemplary embodiment is described in more detail below with reference to the accompanying drawings.

[0059] They show:

[0060] FIG. 1 shows schematically and in a side view an exemplary embodiment of the dense phase powder pump according to the invention;

[0061] FIG. 2 shows a schematic first isometric view of a powder switch used in the dense phase powder pump;

[0062] FIG. 3 schematically shows a second isometric view of the exemplary embodiment of the powder switch;

[0063] FIG. 4 shows a schematic sectional view of the exemplary embodiment of the powder switch;

[0064] FIG. 5 schematically shows a side view of the exemplary embodiment of the powder switch;

[0065] FIG. 6 shows a schematic plan view of the exemplary embodiment of the powder switch;

[0066] FIG. 7 shows a schematic view of the (downstream) front side of the exemplary embodiment of the powder switch; and

[0067] FIG. 8 schematically shows a view of the (upstream) rear side of the exemplary embodiment of the powder switch.

[0068] The exemplary embodiment of the dense phase powder pump 20 according to the invention, shown schematically in FIG. 1, is characterized, firstly, by its modularity. In particular, the dense phase powder pump 20 is constructed according to the building block or modular principle and is divided into various functional components, also constructed in a modular manner.

[0069] This is, in particular, a pump head module 21, which has at least one powder conveying chamber, which is fluidly connected or connectable via a powder inlet to a modular powder switch 1 and via a powder outlet 25 to a powder reservoir or a powder spray device. The pump head module 21 of the dense-phase powder pump 20 is preferably operatively connected, in particular via a quick-change system or quick-change module 22, to a compressed air control module 23, which forms an application valve unit for the pump head module 21 and for the modular powder switch 1.

[0070] The compressed air control module 23 is integrated or can be integrated at least partially or regionally in a pump housing 24, wherein the pump housing 24 further comprises a control unit for controlling the controllable components of the dense phase powder pump 20 (including the powder switch 1).

[0071] The quick-change system or quick-change module 22, via which the pump head module 21 and the powder switch 1 designed as a module are connected to the compressed air control module 23 serving as an application valve unit, is designed in particular as a connection block.

[0072] The powder diverter 1 is provided at the powder inlet of the pump head module 21. Alternatively, the powder diverter 1 can also form the powder inlet of the dense phase powder pump 20.

[0073] Basically, the powder switch 1 is designed to connect the powder inlet of the dense phase powder pump 20 or the pump head module 21 in terms of flow either to a first powder line / channel system opening into a powder chamber of a first powder container or to a second powder line / channel system opening into a powder chamber of a second powder container.

[0074] The structure and operation of the powder switch 1 used in the dense phase powder pump 20 according to FIG. 1 are described in more detail below with reference to the illustrations in FIG. 2 to FIG. 8.

[0075] Specifically, the powder switch 1 has a first powder inlet 2, which is fluidly connected or connectable to the first powder line / channel system. The powder switch 1 further has a second powder inlet 3, which is fluidly connected or connectable to the second powder line / channel system. For this purpose, it is advisable to design the first and second powder inlets 2, 3 of the powder switch 1 as hose connections, to which a powder hose fluidly connected to the corresponding powder reservoir can be connected.

[0076] In addition, the powder switch 1 comprises a powder outlet 4, which is fluidly connected or connectable to the powder inlet of the dense phase powder pump 20 or the pump head module 21 of the dense phase powder pump 20.

[0077] The powder switch 1 further comprises a switching mechanism which is designed to selectively connect the powder outlet 4 of the powder switch 1 either with the first powder inlet 2 of the powder switch 1 or with the second powder inlet 3 of the powder switch 1.

[0078] As can be seen in particular from the sectional view according to FIG. 4, the switching mechanism comprises a corresponding actuator, by means of which the first and second powder inlets 2, 3 of the powder switch 1 can be moved together relative to the powder outlet 4. For this purpose, in the exemplary embodiment shown in the drawings, the actuator has a slide arrangement with a slide 6 that is adjustable and, in particular, linearly displaceable relative to a housing body 7 of the powder switch 1, wherein the powder outlet 4 or the first and second powder inlets 2, 3 is / are formed in the slide 6.

[0079] In the exemplary embodiment shown in the drawings, the first and second powder inlets 2, 3 are formed in the carriage 6, while the powder outlet 4 is formed in the housing body 7 of the powder switch 1.

[0080] Although not directly apparent from the drawings, in the exemplary embodiment of the powder switch 1 according to the invention, the switching mechanism comprises a pneumatic drive associated with the carriage assembly, which is configured to move the carriage 6 relative to the housing body 7, as needed, such that the powder outlet 4 is fluidly connected either to the first powder inlet 2 or to the second powder inlet 3. The drive is designed as a pneumatic drive based on the functional principle of a single-acting cylinder. Therefore, only a single pneumatic connection 8 is provided for the drive.

[0081] In order to realize a design of the powder switch 1 that is as compact as possible, it is advisable for the slide arrangement to have a pretensioning element assigned to the slide 6, in particular in the form of a spring, which is designed to pretension the slide 6 into a first position in which the powder outlet 4 is fluidly connected to the first powder inlet 2.

[0082] In this case, the pneumatic drive is particularly designed to move the carriage 6, when compressed air is supplied via the (single) pneumatic connection 8, against the pretensioning force of the pretensioning element, which is designed in particular in the form of a spring, relative to the housing body 7 from the first position into a second position in which the powder outlet 4 is fluidly connected to the second powder inlet 3.

[0083] Of course, it is also conceivable to use a pneumatic drive for the drive, which is based on the functional principle of a double-acting cylinder and thus has two pneumatic connections.

[0084] The exemplary embodiment of the powder switch 1 according to the invention is characterized in particular in that the powder switch 1 further comprises a purge air inlet 5. The switching mechanism of the powder switch 1 is designed such that the purge air inlet 5 is fluidly connected to the second powder inlet 3 when the powder outlet 4 is fluidly connected to the first powder inlet 2, and that the purge air inlet 5 is fluidly connected to the first powder inlet 2 when the powder outlet 4 is fluidly connected to the second powder inlet 3.

[0085] As shown in the drawings, the purge air inlet 5 is preferably formed in the housing body 7 of the powder switch 1.

[0086] The sectional view according to FIG. 4 shows that a channel system 9 which is in fluid connection with the purge air inlet 5 and has a first purge air outlet 11 and a second purge air outlet 12 is formed in the housing body 7 of the powder switch 1, the channel system having a first purge air outlet 11 and a second purge air outlet 12, wherein the first and second purge air outlets 11, 12 are formed in an end face 10 of the housing body 7 adjacent to the carriage 6 in such a way that the first purge air outlet 11 is in fluid connection with the first powder inlet 2 when the second powder inlet 3 is in fluid connection with the powder outlet 4, and that the second purge air outlet 12 is in fluid connection with the second powder inlet 3 when the first powder inlet is in fluid connection with the powder outlet 4.

[0087] It can also be seen from the sectional view according to FIG. 4 that a mouth opening 13 of the powder outlet 4 is formed in the end face 10 of the housing body 7 adjacent to the slide 6.

[0088] In particular, it is provided that the mouth opening 13 of the powder outlet 4 and the first and second purge air outlets 11, 12 are arranged in a line (here: in a vertical line), wherein the first and second purge air outlets 11, 12 are arranged in an equidistant manner with respect to the mouth opening of the powder outlet 4.

[0089] The slide 6 can be moved from a first position, in which a gap 14 is present between the end face 10 of the housing body 7 adjacent to the slide 6 and the end face of the slide 6 adjacent to the housing body 7, relative to the housing body 7, into a second position, in which the gap 14 between the end face 10 of the housing body 7 adjacent to the slide 6 and the end face of the slide 6 adjacent to the housing body 7 is eliminated or at least reduced, in order to fluidly connect the mouth opening 13 of the powder outlet 4 to the first or second powder inlet 2, 3 and to fluidly connect the corresponding purge air outlet 11, 12 to the second or first powder inlet 3, 2 in a sealing manner.

[0090] Preferably, appropriate seals 15 (sealing rings) are also used here.

[0091] In order to move the slide 6 from the first position to the second position relative to the housing body 7 of the powder switch 1, the slide 6 is assigned a pneumatic drive, which is designed to transfer the slide 6 from the first position to the second position relative to the housing body 7 as needed. The drive is designed, in particular, as a pneumatic drive based on the functional principle of a single-acting cylinder.

[0092] The slide arrangement can have a prestressing element associated with the slide 6, in particular in the form of a spring or elastic element, which is designed to prestress the slide 6 relative to the housing body 7 into the first position.

[0093] As can be seen in particular from a synopsis of FIG. 2, FIG. 3 and FIG. 5, in the exemplary embodiment of the powder switch 1 according to the invention, the pneumatic connection 8 of the first drive, a pneumatic connection 16 of the second drive and a pneumatic connection associated with the purge air inlet 5 are formed in a common side wall region of the housing body 7 (here: in the lower side wall region of the housing body 7).

[0094] The isometric view according to FIG. 2 further shows that in the exemplary embodiment of the powder switch 1 according to the invention, the first powder inlet 2 and the second powder inlet 3 are designed in a carrier 17 and in particular in a carrier plate, wherein the carrier 17 or the carrier plate together with the first and second powder inlets 2, 3 is received and in particular inserted in a receiving area 18 of the carriage 6 and is held there by a quick-release fastener 19.

[0095] The invention is not limited to the exemplary embodiment of the powder switch shown in the drawings, but results from a combination of all features disclosed herein.

[0096] Reference symbol list

[0097] 1 powder softener

[0098] 2 first powder inlet

[0099] 3 second powder inlet

[0100] 4 Powder outlet

[0101] 5 Purge air inlet

[0102] 6 Carriage arrangement / carriage

[0103] 7 Housing body

[0104] 8 Pneumatic connection of the first drive

[0105] 9 channel system

[0106] 10 Front face of the housing body

[0107] 11 first purge air outlet

[0108] 12 second purge air outlet

[0109] 13 Mouth opening of the powder outlet

[0110] 14 gap space

[0111] 15 Seal

[0112] 16 Pneumatic connection of the second drive

[0113] 17 Carrier / carrier plate

[0114] 18 Sled receiving area

[0115] 19 Quick release

[0116] 20 powder dense phase pump

[0117] 21 Pump head module

[0118] 22 Quick-change module / connection block

[0119] 23 Compressed air control module

[0120] 24 pump housing

[0121] 25 Powder outlet of the dense phase powder pump

Claims

Patent claims 1. Powder pump, in particular in the form of a dense phase powder pump (20), for conveying coating powder, wherein the dense phase powder pump (20) is designed to selectively suck in coating powder from a powder chamber of a first powder container or coating powder from a powder chamber of a second powder container via a powder inlet of the dense phase powder pump (20) and to supply the sucked-in coating powder to a powder dispensing device or a powder reservoir via a powder outlet (25) of the dense phase powder pump (20), wherein a powder switch (1) is provided at the powder inlet of the dense phase powder pump (20) or wherein the powder inlet of the dense phase powder pump (20) is designed as a powder switch (1), wherein the powder switch (1) is designed,to connect the powder inlet of the dense phase powder pump (20) either to a first powder line / channel system opening into the powder chamber of the first powder container or to a second powder line / channel system opening into the powder chamber of the second powder container.

2. Dense-phase powder pump (20) according to claim 1, wherein the powder switch (1) comprises: a first powder inlet (2) which is fluidly connected or connectable to the first powder line / channel system; a second powder inlet (3) which is fluidly connected or connectable to the second powder line / channel system; a powder outlet (4) which is fluidly connected to the powder inlet of the powder pump or, via a powder inlet valve, to a powder feed chamber of the dense-phase powder pump (20); and a switching mechanism which is designed to selectively connect the powder outlet (4) of the powder switch (1) either with the first powder inlet (2) of the powder switch (1) or with the second powder inlet (3) of the powder switch (1).

3. Dense-phase powder pump (20) according to claim 2, wherein the powder switch (1) further comprises a purge air inlet (5), and wherein the switching mechanism of the powder switch (1) is designed such that the purge air inlet (5) of the powder switch (1) is fluidly connected to the second powder inlet (3) of the powder switch (1) when the powder outlet (4) of the powder switch (1) is fluidly connected to the first powder inlet (2) of the powder switch (1), wherein the switching mechanism of the powder switch (1) is preferably further designed such that the purge air inlet (5) of the powder switch (1) is fluidly connected to the first powder inlet (2) of the powder switch (1) when the powder outlet (4) of the powder switch (1) is fluidly connected to the second powder inlet (3) of the powder switch (1).

4. Dense-phase powder pump (20) according to claim 3, wherein the switching mechanism comprises a carriage arrangement with a carriage (6) which is adjustable and in particular linearly displaceable relative to a housing body (7) of the powder switch (1), wherein the first and second powder inlets (2, 3) of the powder switch (1) are formed in the carriage (6), while the powder outlet (4) is formed in the housing body (7) of the powder switch (1).

5. Powder dense phase pump (20) according to claim 4, wherein the purge air inlet (5) of the powder switch (1) is formed in the housing body (7) of the powder switch (1).

6. Powder dense phase pump (20) according to one of claims 2 to 5, wherein the switching mechanism has a first drive associated with the carriage arrangement, which is designed to move the carriage (6) relative to the housing body (7) of the powder switch (1) as required, such that the powder outlet (4) of the powder switch (1) is fluidly connected either to the first powder inlet (2) of the powder switch (1) or to the second powder inlet (3) of the powder switch (1).

7. Powder dense phase pump (20) according to claim 6, wherein the first drive is designed as a pneumatic drive and has at least one pneumatic connection (8).

8. Dense-phase powder pump (20) according to claim 7, wherein the carriage arrangement has a prestressing element, in particular in the form of a spring, which is assigned to the carriage (6), which is designed to prestress the carriage (6) into a first position in which the powder outlet (4) of the powder switch (1) is fluidically connected to the first powder inlet (2) of the powder switch (1), wherein the pneumatic drive is designed, when compressed air is supplied via the pneumatic connection (8), to move the carriage (6) against the prestressing force of the prestressing element, in particular in the form of a spring, relative to the housing body (7) of the powder switch (1) from the first position into a second position in which the powder outlet (4) of the powder switch (1) is fluidically connected to the second powder inlet (3) of the powder switch (1).

9. Dense-phase powder pump (20) according to one of claims 2 to 8, wherein a channel system (9) is formed in the housing body (7) of the powder switch (1) and is in fluid communication with the purge air inlet (5) of the powder switch (1), said channel system having a first purge air outlet (11) and a second purge air outlet (12), wherein the first and second purge air outlets (11, 12) are formed in an end face (10) of the housing body (7) of the powder switch (1) adjacent to the carriage (6) in such a way that the first purge air outlet (11) is in fluid communication with the first powder inlet (2) of the powder switch (1) when the second powder inlet (3) of the powder switch (1) is in fluid communication with the powder outlet (4), and that the second purge air outlet (12) is in fluid communication with the second powder inlet (3) of the powder switch (1) when the first powder inlet (2) is in fluid connection with the powder outlet (4) of the powder switch (1).

10. Dense-phase powder pump (20) according to claim 9, wherein an orifice (13) of the powder outlet (4) of the powder switch (1) is formed in the end face (10) of the housing body (7) of the powder switch (1) adjacent to the carriage (6), and wherein the orifice (13) of the powder outlet (4) and the first and second purge air outlets (11, 12) of the powder switch (1) are arranged in a line, the first and second purge air outlets (11, 12) being arranged equidistantly with respect to the orifice (13) of the powder outlet (4).

11. Dense-phase powder pump (20) according to claim 9 or 10, wherein the carriage (6) can be moved from a first position, in which a gap (14) is present between the end face (10) of the housing body (7) of the powder switch (1) adjacent to the carriage (6) and the end face of the carriage (6) adjacent to the housing body (7), relative to the housing body (7) of the powder switch (1) into a second position, in which the gap (14) between the end face (10) of the housing body (7) of the powder switch (1) adjacent to the carriage (6) and the end face of the carriage (6) adjacent to the housing body (7) is eliminated or at least reduced.

12. Powder dense phase pump (20) according to claim 11, wherein the carriage arrangement has a second drive which is designed to transfer the carriage (6) relative to the housing body (7) of the powder switch (1) from the first position to the second position as required, wherein the second drive is preferably designed as a pneumatic drive and has a pneumatic connection (16).

13. Powder dense phase pump (20) according to claim 11 or 12, wherein the carriage arrangement has a prestressing element associated with the carriage (6), in particular in the form of a spring or an elastic element, which is designed to prestress the carriage (6) relative to the housing body (7) of the powder switch (1) into the first position.

14. Dense-phase powder pump (20) according to one of claims 2 to 13, wherein the first powder inlet (2) and the second powder inlet (3) are designed in a carrier (17) and in particular in a carrier plate, wherein the carrier (17) or the carrier plate together with the first and second powder inlets (2, 3) is received and in particular inserted in a receiving area (18) of the carriage (6) and is held there preferably via a quick-release fastener (19).

15. A dense phase powder pump (20) according to any one of claims 1 to 14, wherein the dense phase powder pump (20) is characterized by its modular design and comprises at least the following components, each designed as a module: a pump head module (21) having at least one powder conveying chamber which is or can be fluidly connected via the powder inlet either to the powder chamber of the first powder container or to the powder chamber of the second powder container and via a powder outlet (25) to a powder reservoir or to a powder spraying device; and a compressed air control module (23) having a plurality of switching valves which are assigned in particular to pneumatically controllable components of the pump head module (21) and are designed to supply the pneumatically controllable components of the pump head module (21) with compressed air or suction air orTo supply negative pressure, wherein the powder switch (1) is in particular part of the pump head module (21).

16. Dense phase powder pump (20) according to claim 15, wherein the compressed air control module (23) of the dense phase powder pump (20) further comprises switching valves which are assigned to the powder switch (1) for supplying compressed air to the purge air inlet (5) of the powder switch (1) as required, for supplying compressed air to the pneumatic connection (8) of the first drive of the powder switch (1) designed as a pneumatic drive, and / or for supplying Compressed air to the pneumatic connection (16) of the second drive of the powder switch (1), which is designed as a pneumatic drive.

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