POWDER SPRAY COATING BOOTH

Abstract

The invention relates to a powder spray coating booth (1) in which objects can be coated with powder with the aid of at least one spray device (6), wherein the powder spray coating booth (1) has an exhaust channel arrangement for exhausting air and excess powder from the booth interior of the powder spray coating booth (1), and wherein the exhaust channel arrangement has an exhaust channel (9) which is arranged in the booth substructure and which is fluidically connected to the booth interior via at least one exhaust opening (8). In order to achieve that a change of powder can also be quickly carried out, the invention provides that the exhaust channel (9) is additionally fluidically connected or can be additionally fluidically connected to at least two channel sections (31, 32) which are led out of the booth substructure, via a manifold (30) arranged in the booth substructure.

Claims

1. A powder spray coating booth (1) in which objects can be coated with powder by means of a spraying device (6), wherein the powder spray coating booth (1) comprises a suction channel arrangement for suctioning air and excess powder out of the booth interior of the powder spray coating booth (1), and wherein the suction channel arrangement has a suction channel (9) disposed in the booth substructure which is fluidly connected to the booth interior by means of at least one exhaust vent (8), the suction channel (9) is further fluidly connected or connectable to at least two channel sections (31, 32) leading out of the booth substructure by means of a manifold (30) arranged in the booth substructure, characterized in that the manifold (30) is configured as a T-piece or a Y-piece having one inlet and two outlets, wherein the inlet of the manifold (30) is fluidly connected or connectable to the suction channel (9) and the two outlets of the manifold (30) are each fluidly connected or connectable to a respective one of the channel sections (31, 32) leading out of the booth substructure; or the manifold (30) is of star-shaped or cross-shaped configuration and comprises one input and a plurality of outlets, wherein the inlet of the manifold (30) is fluidly connected or connectable to the suction channel (9) and the plurality of outlets of the manifold (30) are each fluidly connected or connectable to a respective one channel section (31, 32) leading out of the booth substructure.

2. (canceled)

3. (canceled)

4. The powder spray coating booth (1) according to claim 1, wherein the suction channel (9) provided in the booth substructure is preferably centrally arranged, and wherein the suction channel (9) is fluidly connected to the booth interior by means of a least one suction slot.

5. The powder spray coating booth (1) according to claim 1, wherein a flow-switching device is provided to alternatingly form and cut off a fluid connection between the suction channel (9) disposed in the booth substructure and one of the at least two channel sections (31, 32) leading out of the booth substructure.

6. The powder spray coating booth (1) according to claim 1, wherein each of the channel sections (31, 32) leading out of the booth substructure is allocated a powder separator (10, 20), to which the respective channel section (31, 32) can be alternatingly fluidly connected and connectable by means of a flow-switching device (33, 34) allocated to the respective channel section (31, 32).

7. The powder spray coating booth (1) according to claim 5 or 6, wherein the flow-switching device (33, 34) comprises at least one valve flap or at least one valve gate and preferably exactly one valve flap or exactly one valve gate per channel section (31, 32) leading out of the booth substructure in order to cut off a fluid connection between the relevant channel section and the powder separator (10, 20) associated with said channel section (31, 32) when needed.

8. The powder spray coating booth (1) according to claim 6 or 7, wherein the powder separator comprises a cyclone system (21) and/or a system (22).

9. The powder spray coating booth (1) according to claim 1, 4, 5, 6, 7, or 8, wherein a first channel section (31) leading out of the booth substructure is fluidly connected or connectable to a first powder separator (10), and wherein a second channel section (32) leading out of the booth substructure is fluidly connected or connectable to a second powder separator (20), and wherein a first type of powder or color of powder being or to be sprayed in the powder spray coating booth (1) is allocated to the first powder separator (10) and a second type of powder or color of powder being or to be sprayed in the powder spray coating booth (1) is allocated to the second powder separator (20).

Description

[0023] The following will reference the drawings in describing an example embodiment of the powder spray coating booth according to the invention in greater detail.

[0024] Shown are:

[0025] FIG. 1 a schematic top view of an example embodiment of the powder spray coating booth according to the invention in a first operating state; and

[0026] FIG. 2 a schematic top view of the example embodiment of the inventive powder spray coating booth in a second operating state.

[0027] The powder spray coating booth 1 according to the invention depicted in the drawings contains two object wall passages 2 and 4 arranged diametrically opposite from one another for the conveying of objects to be coated through the powder spray coating booth 1. The powder spray coating booth 1 is further provided with a booth floor 3.

[0028] The width of the object wall passages 2 and 4 limits the maximum width of the object transport path; i.e. the maximum width of the coatable objects inside the powder spray coating booth 1.

[0029] Positioning devices 5 are laterally arranged external of the powder spray coating booth 1, for example in the form of lifting stands, which each support at least one spraying device 6 (in the drawings exactly two) and which can move up and down vertically to coat an object to be coated with powder in the booth interior of the powder spray coating booth 1. To this end, each spraying device 6 extends from the positioning device 5 into the interior of the booth through a respective vertical wall slot 7 of the powder spray coating booth 1.

[0030] The object to be coated is transported through the powder spray coating booth 1 transverse to the longitudinal direction of the spraying devices 6 by a transport mechanism, for example a continuous conveyor belt.

[0031] The spraying devices 6 preferably comprise one or more high-voltage electrodes for electrostatically charging the coating powder and a high-voltage generator for producing the high voltage for the high-voltage electrodes.

[0032] The powder spray coating booth 1 depicted schematically in the drawings exhibits a rectangular booth wall when viewed in horizontal section and a booth floor 3 which separates the booth interior of the powder spray coating booth 1 from the booth substructure.

[0033] In the context of the present description, all the elements which are disposed in a powder spray coating booth 1 below the path of movement of the coating objects to be coated and below the spray jets of the spraying devices, the latter also known as spray guns, are collectively referred to as the booth floor. The booth substructure identifies the space underneath the booth floor 3.

[0034] At least one longitudinally extending longitudinal floor slot 8 is formed in the booth floor 3 of the powder spray coating booth 1. This at least one longitudinal floor slot 8 fluidly connects the booth interior of the powder spray coating booth 1 to a suction channel 9. Dotted lines are used to depict the suction channel 9 in the drawings since it is arranged underneath the booth floor 3; i.e. in the booth substructure of the powder spray coating booth 1. As can further be seen from the drawings, the suction channel 9 arranged in the booth substructure preferably extends over the entire length of the booth.

[0035] The suction channel 9 disposed in the booth substructure is part of a suction channel arrangement via which excess powder can be suctioned out of the booth interior. To this end, the excess powder which drops during the spraying of coating powder is drawn off into the suction channel 9 through the at least one longitudinal floor slot 8. The suction channel 9 is connected by means of a fluid line system to at least one powder suction mechanism, preferably to at least one powder separator for recovering powder.

[0036] In the example embodiment of the inventive powder spray coating booth 1 depicted in the drawings, two independently connectable powder separators 10, 20 are employed as the powder recovery device for recovering the excess powder suctioned out of the booth interior:

[0037] Firstly, a first powder separator 10 designed as a filter unit is provided here which serves in separating powder out of the powder/air suction flow drawn out of the booth interior and thereafter in blowing air purged of powder out into the environment.

[0038] The powder separated by the filter unit of the first powder separator 10 falls into a powder container and can then be re-fed to the spraying devices 6 via a powder line, preferably together with fresh powder. Means for treating the powder, e.g. a sieve, can be arranged in the flow path between the filter unit and the powder container.

[0039] Secondly, a cyclone unit 21 with a downstream filter unit (afterfilter 22) is provided in the embodiment depicted schematically in the drawings as an example further powder separator 20. The cyclone unit 21 has a cyclone flow inlet 21a and a cyclone air outlet 21b as well as a cyclone mechanism in the flow path between the two for separating powder out of the powder/air suction flow by the cyclone centrifugal forces. The cyclone flow inlet 21a is formed at the upstream start of a cyclone line (duct or tube). The cyclone air outlet 21b is connected to the afterfilter 22 which filters out the remaining powder which the cyclone mechanism is unable to separate out.

[0040] As is also the case with the filter unit of the first powder separator 10, the powder separated by the afterfilter 22 falls into a powder container and can then be re-fed to the spraying devices 6, preferably together with fresh powder, via a powder line. The powder separated out of the powder/air flow by the cyclone unit 21 of the second powder separator 20 falls through a cyclone powder outlet at the bottom of the cyclone into a collection container. The powder in the collection container can be deemed waste or can be treated and fed back to the spraying devices 6 in the same way as the powder of the filter unit's powder container.

[0041] Although a filter unit is provided as the first powder separator 10 and a cyclone unit 21 with a downstream filter unit provided as the second powder separator 20 in the example embodiment depicted in the drawings, this realization of the powder separators 10, 20 is not to be regarded as being restrictive. In fact, it is for example also conceivable for both powder separators 10, 20 to each be configured as a filter unit or as a cyclone unit with a downstream filter unit.

[0042] In order to alternatingly conduct the flow of the powder/air mixture through the first powder separator 10 or through the second powder separator 20, the powder spray coating booth 1 comprises a manifold 30 disposed in the booth substructure which has at least two channel sections 31, 32 leading out from the booth substructure.

[0043] In the example embodiment depicted in the drawings, the manifold 30 arranged in the booth substructure is of T-shaped configuration and comprises an inlet fluidly connected to the suction channel 8. Each of the two outlets of the manifold 30 is fluidly connected to one respective channel section 31, 32 leading out (laterally) from the booth substructure.

[0044] A flow-switching device 33, 34 is allocated to each channel section 31, 32 in order to cut off a fluid connection between the respective channel section 31, 32 and a powder separator 10, 20 associated with the channel section 31, 32 when needed.

[0045] In the operating state of the example embodiment of the inventive powder spray coating booth 1 depicted schematically in FIG. 1, the flow-switching device 32 associated with the lower channel section 32 is open, for example, so that the lower channel section 32 is fluidly connected to the associated second powder separator 20 (here: cyclone unit and afterfilter).

[0046] At the same time, the flow-switching device 33 allocated to the upper channel section 31 is closed so that a fluid connection between the upper channel section 31 and associated first powder separator 10 (here: filter means) is cut off.

[0047] FIG. 2 shows an operating state of the powder spray coating booth 1 in which the flow-switching device 33 allocated to the upper channel section 31 is open and the flow-switching device 34 allocated to the lower channel section 32 is closed. In consequence thereof, the upper channel section 31 is fluidly connected to the correspondingly associated first powder separator 10 while a fluid connection between the lower channel section 32 and associated second powder separator 20 is cut off.

[0048] In the embodiment depicted in the drawings, the flow-switching devices 33, 34 are respectively realized as manually actuatable shut-off mechanisms able to be extended and/or retracted into and out of the flow path in order to clear/block the fluid connection between the respective channel section 31, 32 and associated powder separator 10, 20. It is however of course also conceivable for these shut-off mechanisms to be implemented so as to be electrically, pneumatically or hydraulically actuatable. Also conceivable is selecting other embodiments for the flow-switching devices 33, 34 such as, for example, valve flaps, valve gates, etc.

[0049] The powder spray coating booth 1 according to the invention enables multi-color operation without laborious cleaning when changing colors by virtue of being able to connect different powder separators 10, 20 as needed. If, for example, a specific (main) color has been allocated to the first powder separator 10, the fluid connection between the first powder separator 10 and the booth interior can be cut off upon changing color from the main color to another color while a fluid connection between the booth interior and the second powder separator 20 is opened.

[0050] The invention is not limited to embodiments which make use of only two different powder separators 10, 20. It is in fact also conceivable for even more powder separators to be alternatingly connected. In this case, the manifold 30 disposed in the booth substructure should exhibit a star-shaped configuration.

[0051] The invention is in particular also characterized by the largest part of the suction channel arrangement being disposed in the booth substructure of the powder spray coating booth 1 such that there is essentially no change to the amount of space occupied by the powder spray coating booth 1.

[0052] The invention is not limited to powder spray coating booths having a substantially rectangular booth interior. On the contrary, the invention is obviously also advantageous in combination with a vertically cylindrical booth.