WO2018072909A1

WO2018072909A1 - Cyclone separator

Info

Publication number: WO2018072909A1
Application number: PCT/EP2017/069936
Authority: WO
Inventors: Patrik Broger
Original assignee: Gema Switzerland Gmbh
Priority date: 2016-10-21
Filing date: 2017-08-07
Publication date: 2018-04-26
Also published as: DE102016120078A1

Abstract

The invention relates to a cyclone separator (100), in particular for a powder recovery apparatus in an enamel powder coating plant. The cyclone separator (100) has an inflow region (101) with a powder inlet (102) for a powder-air mixed flow, a separation region (103) which adjoins the lower end of the inflow region (101) and which serves for separating off at least a part of the powder contained in the mixed flow under the action of centrifugal force, a powder collecting region (104) which is connected or connectable to the lower end region (103a) of the separation region (103) and which serves for collecting the powder separated off in the separation region (103), and an immersion tube which opens centrally from above into the inflow region (101) and which serves for discharging air from the mixed flow. The invention is characterized in that at least the inner surface, which comes into contact with the powder-air mixed flow, of the inflow region (101) and/or at least the inner surface, which comes into contact with the powder-air mixed flow, of the separation region (103) is manufactured at least in regions from a material which has a Rockwell hardness C (R_c) of at least 60.

Description

CYCLONA EIDER

description

The invention relates to a cyclone separator according to the preamble of patent claim 1.

Accordingly, the invention particularly relates to cyclone separators for a powder recovery device in an enamel powder coating plant.

Furthermore, the invention relates to a powder recovery device for an enamel powder coating system, wherein the powder recovery device comprises the cyclone separator according to the invention.

Cyclone separators are well known in the art of exhaust gas purification and serve to separate solid particles contained, for example, in a powder-air mixture stream. In a cyclone separator, the mixture stream to be treated, in contrast to a centrifuge, is set in a rotary motion by its own flow velocity and a corresponding structural design of the separator. The centrifugal forces acting on the powder particles of the mixture flow accelerate them radially outwards and are thereby separated from the gas flow, which is conducted inwards and removed in the cyclone separator.

A cyclone separator of the type considered here essentially consists of an inlet region, for example in the form of a cylindrical container, where a separation region is located below the inlet region, in particular with a conical end region in which the centrifugal force separation of at least part of the powder contained in the mixture flow takes place. The inlet area of the cyclone separator is usually supplied tangentially with the powder-air mixture stream to be treated. For this purpose, different inlet geometries are conceivable, such as a spiral inlet, a tangential inlet, a helical inlet or an axial inlet.

The inlet geometry produces a rotary flow of the mixture flow in the interior of the cyclone separator. As a result of the centrifugal forces acting on them, the powder particles to be separated off from the mixed flow sediment to the outer wall of the separation region and are conveyed downwards in a spiral-collecting region along a wall boundary layer flow in spiral paths along a cone formed at the lower end region of the separation region. The gas flow is thereby forced to reverse upwards. The gas leaves the cyclone separator in the form of a radial flow from outside to inside and flows through a so-called dip tube at the top of the cyclone separator upwards. The inlet geometry of the cyclone separator and the dip tube of the cyclone separator form an important component of the cyclone separator, since its geometry and diameter determine the centrifugal force occurring in the cyclone separator and thus the separation efficiency as well as the pressure loss. The other dimensions of the areas of the cyclone separator are adapted to the inlet geometry and the dip tube.

The types of cyclone separators differ essentially by the inlet geometries. The most common inlet geometries are the spiral inlet and the tangential inlet, also called slot inlet. Since both are equivalent in terms of the separation efficiency, the simpler tangential inlet is often preferred. The axial inlet is partly required for space reasons. It is particularly suitable for large gas flow rates with slightly lower separation efficiency. A cyclone separator of the type mentioned is known for example from the document DE 10 2007 005 312 AI. In this prior art, the cyclone separator for depositing coating powder comes from a Powder-air mixture flow is used. It is envisaged that the deposited in the separation region of the cyclone separator powder can be recycled as a recovery powder to a powder spray coating system. Before the powder separated from the powder-air mixture stream and thus recovered can be reused as recovery powder in a powder coating system - either pure or mixed with fresh powder - it may be necessary to recycle the recovery powder so that it has sufficiently high quality , This may include, among other things, the screening of the recovery powder in a screening device in order to be able to separate coarse-grained impurities from the recovered coating powder.

Moreover, it is known to use upstream or downstream of the cyclone separator a suitable screening device, for example in the form of a separate screen. Furthermore, it is basically possible to provide in the cyclone separator itself a screen for sieving the powder separated from the powder-air mixture stream.

When using cyclone separators in a powder recovery device of a (thermoset) powder coating system (equipment for coating objects with thermosetting powder), the special feature is that, depending on the coating operation, the gas throughput through the cyclone separator varies. This gas throughput depends in particular on the amount of air provided with residual powder for the purpose of powder deposition of a coating booth of the powder coating unit per unit time is fed to the cyclone separator.

In addition, it should be noted that (thermoset) powder coating systems are generally operated with different powder types and powder types. In this respect, it is usually not possible to provide an optimally adapted to the operation of the powder coating plant cyclone, since - as stated - varies in particular the per unit time the cyclone supplied amount of the treated powder-air mixture stream during operation of the powder coating plant. The usually not optimally achievable adaptation of the cyclone separator to the actual operation of the powder coating system has the consequence that the cyclone usually does not achieve optimum separation efficiency. The separation efficiency of the cyclone is further reduced if in the powder-air mixture stream to be treated particularly abrasive powder particles are included, which is the case, for example, when in the powder coating plant enamel powder or ceramic-containing powder is sprayed. Such in the cyclone separator supplied powder-air mixture stream contained abrasive particles change due to their abrasive behavior, the surface finish of the inner surface of the cyclone. It has been shown that roughening of the inner surface of the cyclone separator after a short time is inevitable especially with enamel powder. Investigations have also shown that a roughened surface condition of the inner surface of the cyclone separator can in part have significant effects on the flow behavior of the mixture stream rotating in the cyclone separator. In particular, a roughened surface finish affects the wall boundary layer flow, which has a significant influence on the deposition of the powder particles carried in the mixture stream. By roughening the inner surface of the cyclone separator, the boundary layer becomes increasingly turbulent, with the result that an additional radial force counteracts the centrifugal force on the powder particles carried in the wall boundary layer flow so that the powder particles are again transported radially out of the wall boundary layer flow into the turbulent flow , This ultimately has a significant influence on the separation efficiency of the cyclone separator.

On the basis of this problem, the present invention seeks to optimize the achievable in the operation of a cyclone separation efficiency or achievable during operation of the cyclone separation efficiency, through a simple construction of the cyclone to ultimately achieve higher reliability and lower operating costs , This object is achieved by the subject matter of independent claim 1, wherein advantageous developments of the cyclone separator according to the invention are specified in the dependent claims. Accordingly, it is provided in particular that, in the cyclone separator according to the invention, at least the inner surface of the inlet region coming into contact with the powder-air mixture stream and / or at least the inner surface of the deposition region coming into contact with the powder-air mixture stream at least partially consists of a particularly hard, is made of resistant material having a Rockwell hardness C (Rc) of at least 60. The effects achieved with the solution according to the invention are obvious: by the inner surface of the cyclone, and in particular the inner surface of the inlet region and / or the inner surface of the separation region of the cyclone, at least partially made of the material having a Rockwell hardness C (Rc ) of at least 60, can be achieved in an easy to implement, yet effective way that the surface finish of the corresponding inner surface of the cyclone even with prolonged operation and even if in the mixture to be treated highly abrasive powder particles are included, a laminar Wall boundary layer flow can be formed in the separation region, with which the powder particles to be separated from the mixture flow as a result of the centrifugal force acting on them in spiral tracks along the cone formed at the lower end of the Abscheidebereiches down n be promoted in the powder collection area. In particular, the solution according to the invention effectively prevents the wall boundary layer flow from becoming turbulent, which, as stated at the outset, has a significant influence on the separation efficiency that can be achieved during operation of the cyclone separator.

Thus, it should be noted that the separation efficiency of the cyclone separator can be optimized by the proposed measure, namely to produce at least the inner surface of the cyclone separator which comes into contact with the powder-air mixture flow at least in regions from a hard material.

The cyclone separator according to the invention is particularly suitable for a powder recovery device in an enamel powder coating system. In particular, enamel powder differs from thermosetting coating powders in that enamel powder is highly abrasive, so that the components of the spray coater that occur during spray coating with enamel powder in contact with the enamel powder must be specially designed. For example, so far in enamel powder coating systems particularly resistant sintered filters are used as a powder recovery device, since with enamel powder, a conventional cyclone separator would rub through within a short time. With the solution according to the invention, however, it is now possible for the first time to use the Zyklonabscheidertechnik in enamel powder coating systems.

In a preferred realization of the cyclone separator according to the invention, it is provided that the lower end region of the separation region is frusto-conical with a sheathing tapering in the direction of the powder collection region, in particular conically tapering shell geometry, whereby in particular the inner surface of the truncated conical end region of the deposition region is made of the material at least in regions which has a Rockwell hardness C (Rc) of at least 60. In this way, also effective abrasive effects on the inner surface in the region of the cyclone separator is prevented, in which the gas flow is still reversed above to be discharged via the dip tube of the cyclone separator from the cyclone. Preferably, the material having a Rockwell hardness C (Rc) of at least 60 is a cemented carbide, a cemented carbide alloy, a metal carbide, a ceramic material, in particular an enamel, a nitride, boride, oxide and / or a diamond material. According to other embodiments, the material used is tungsten carbide, titanium carbide, chromium carbide, boron carbide and / or iron carbide.

In order to fabricate the inner surface of the cyclone separator at least partially with the hard material, it is provided that the inner surface of the region, which is made of the material with the Rockwell hardness C (Rc) of at least 60, is an integral part of the cyclone. Alternatively, it is also conceivable to form the region of the inner surface as a coating or as an insert. According to a further advantageous aspect, the inner surface, in particular of the region which is made of the material, which has a rockwell hardness C (Rc) of at least 60, at least in some areas a roughness (Ra) of <0.20 μιτι and preferably a roughness (Ra) of <0.12 μιτι on. These roughness values are particularly adapted to the mean powder grain size of conventional coating powder and selected so that in the operation of the cyclone separator unwanted powder deposits and accumulations on the inner surface of the cyclone are effectively prevented.

For this purpose, it should be emphasized that the roughness values mentioned are chosen in particular as a function of the mean powder grain size of the coating powder to be separated off with the cyclone separator. In one embodiment of the invention, it is provided in this context in particular that the inner surface and in particular the region of the inner surface, which is made of the material which has a Rockwell hardness C (Rc) of at least 60, is aftertreated or can be treated, In particular, it can be polished and / or sanded in order, if necessary, to adapt the roughness value of the inner surface to the powder type to be deposited.

Further advantageous embodiments of the cyclone separator according to the invention are specified in the dependent claims. The invention further relates to a powder recovery apparatus for a powder coating apparatus, wherein the powder powder recovery apparatus for a powder coating apparatus, wherein the powder recovery apparatus comprises a cyclone separator according to the present invention. The invention will now be described by way of example with reference to the accompanying drawings, given by way of preferred embodiments.

In the drawings: FIG. 1 schematically shows a powder spray coating system as an example of a

Variety of different spray coating equipment, in which a Cyclone separator according to the invention is applicable as a powder recovery device; and

FIG. 2 is a vertical axial section, partially schematically, through a lower

End region of an exemplary embodiment of the cyclone separator according to the invention.

FIG. 1 schematically shows an embodiment of a powder spray coating plant for spray-coating objects 2 with coating powder, which is then melted onto the object in a heating furnace (not shown). The in FIG. 1 powder spray coating plant has a cyclone separator 100 according to the invention.

One or more electronic control units 3 are provided for controlling the functions of the powder spray coating system. For pneumatic conveying of the coating powder powder pumps 4 are provided. These can be injectors in which coating powder is sucked from a powder container by means of compressed air used as conveying air, after which the mixture of conveying air and coating powder then flows together into a container or to a spraying device.

As a powder pump and those types of pumps can be used which convey small portions of powder by means of compressed air in succession, each one small powder portion (powder) stored in a powder chamber and then forced out of the powder chamber by means of compressed air. The compressed air remains behind the powder portion and pushes the powder portion in front of him. These types of pumps are sometimes referred to as pneumatic push pumps or plug-lift pumps because the compressed air pushes the stored powder portion through a pump outlet line like a plug.

To generate the compressed air for the pneumatic conveying of the coating powder and for fluidizing the coating powder, a compressed air source 6 is provided, which via corresponding Druckeinstellelemente 8, z. B. pressure regulator and / or valves, is connected to the various devices. Fresh powder from a powder supplier is supplied from a supplier container, which may for example be a small container 12 or, for example, a large container 14, by means of a powder pump 4 in a fresh powder line 16 or 18 to a screening device 10.

The coating powder sieved by the sieve device 10 is conveyed by gravity or preferably in each case by a powder pump 4 via one or more powder feed lines 20 through powder inlet openings 26 into an intermediate container chamber 22 of an intermediate container 24. The volume of the intermediate container chamber 22 is preferably substantially smaller than the volume of the fresh powder small container 12.

According to a preferred embodiment of the invention, the powder pump 4 of the at least one powder supply line 20 to the intermediate container 24 is a compressed air push pump. Here, the initial portion of the powder supply line 20 may serve as a pump chamber, in which sieved by the sieve 10 powder through a valve, for. B. a pinch valve falls. After this pumping chamber contains a certain powder portion, the powder supply line 20 is fluidically separated by closing the valve of the screening device 10. Thereafter, the powder portion is pushed by compressed air through the powder supply line 20 into the intermediate container chamber 20.

The powder inlet openings 26 are preferably arranged in a side wall of the intermediate container 24, preferably near the bottom of the intermediate container chamber 22, so that when flushing the intermediate container chamber 22 by means of compressed air also on the ground located powder residues can be driven out by the powder inlet 26, for which purpose the powder supply lines 20 preferably separated from the screening device 10 and directed into a waste container, as shown in FIG. 1 is indicated schematically by a dashed arrow 28. For cleaning the intermediate container chamber 22, for example, a plunger 30 provided with compressed-air nozzles can be moved through the intermediate container chamber 22. At one or preferably more Pulverauslassöffnungen 36 are powder pumps 4, z. B. injectors, connected to spray devices 40 for conveying coating powder through powder lines 38. The spray devices 40 may include spray nozzles or rotary atomizers for spraying the coating powder 42 onto the object 2 to be coated, which is preferably located in a coating booth 43. The powder outlet openings 36 are preferably located in a wall opposite the wall in which the powder inlet openings 26 are located. The powder outlet openings 36 are preferably also located near the bottom of the intermediate container chamber 22.

Coating powder 42, which does not adhere to the object 2, is sucked as excess powder via a surplus powder line 44 into a cyclone separator 100 by means of a suction air flow of a blower 46. The excess powder is separated in Zyklonabscheider 100 as far as possible from the suction air stream. The separated powder fraction is then recycled as recovery powder from the cyclone separator 100 via a powder recovery line 50 to the surge tank chamber 22.

Depending on the type of powder and / or degree of powder contamination, it may also be possible to separate the powder recovery line 50 from the intermediate container chamber 22 and to guide the recovery powder into a waste container, as shown in FIG. 1 is shown schematically by a dashed line 51. The intermediate container 24 may have one or more, for example, two sensors Sl and / or S2, to control the supply of coating powder in the intermediate container chamber 22 by means of the control unit 3 and the powder pumps 4 in the powder feed lines 20. For example, the lower sensor Sl detects a lower powder level limit and the upper sensor S2 detects an upper powder level.

The lower end region of the cyclone separator 100 serves as a powder collecting region 104 and can be designed and used as a reservoir for recovery powder. be used and provided for this purpose with one or more sensors, in the illustrated embodiments of the cyclone 100 according to the invention with exactly one sensor S3, which are functionally connected to the control unit 3. Thereby, for example, the fresh powder supply can be automatically stopped by the fresh powder supply lines 16 and 18 as long as there is enough recovery powder in the cyclone separator 100 to supply the intermediate tank chamber 22 recovery powder in sufficient amount required for the spray coating operation by means of the spray devices 40. If there is no longer sufficient recovery powder in the cyclone separator 100, it is possible to switch over automatically to the supply of fresh powder through the fresh powder supply lines 16 or 18. Further, it is also possible to simultaneously supply fresh powder and recovery powder to the intermediate tank chamber 22 so as to be mixed with each other.

The exhaust air of the cyclone separator 100 passes through a dip tube (not explicitly shown) which opens centrally from above into the inlet region 101 and an exhaust air line 54 into a secondary filter device 56 and through one or more filter elements 58 to the blower 46 and after this into the outer chamber. phere. The filter elements 58 may be filter bags or filter cartridges or filter plates or similar filter elements. The powder separated from the air stream by means of the filter elements 58 is normally waste powder and falls by gravity into a waste container or, as shown in FIG. 1, via one or more waste lines 60, which each contain a powder pump 4, are conveyed into a waste container 62 at a waste station 63.

Depending on the powder type and powder coating conditions, the waste powder may also be recovered to the screening device 10 to re-enter the coating circuit. This is shown in FIG. 1 schematically represented by switches 59 and branch lines 61 of the waste lines 60.

In the case of multicolor operation, in which different colors are sprayed only for a short time in each case, the cyclone separator 100 and the postfilter device 56 are usually used and the waste powder of the postfilter device 56 Although the powder separation efficiency of the cyclone 100 is usually lower than that of the postfilter 56, it can be cleaned faster than the postfilter 56. In single-color operation where the same powder is used for a long time, it is It is possible to dispense with the cyclone separator 100 and to connect the surplus powder pipe 44 to the afterfilter device 56 instead of the exhaust pipe 54 and to connect the waste pipes 60 containing powder to be recovered in this case to the screening apparatus 10 as recovery powder pipes. In single-color operation, the cyclone separator 100 is usually used in combination with the post-filter device 56 only if it is a problematic coating powder. In this case, only the recovery powder of the cyclone 100 is fed via the powder recovery line 50 to the intermediate container chamber 22, while the waste powder of the post-filter device 56 is discharged as waste into the waste container 62 or into another waste container, the latter without waste lines 60 directly below an outlet opening of the afterfilter device 56 can be made.

At the lower end of the powder collection area 104 of the cyclone device 100, an outlet valve 64, for example a pinch valve, may be provided. Furthermore, a fluidizing device 66 for fluidizing the coating powder can be provided above this outlet valve 64, in or at the lower end of the powder collecting region 104 of the cyclone separator 100 formed as a reservoir. The fluidizing device 66 includes at least one fluidising wall

80 made of open-pore or narrow-bore material, which is permeable to compressed air, but not for coating powder. The fluidizing wall 80 is between the powder path and a fluidizing compressed air chamber

81 arranged. The fluidizing compressed-air chamber 81 can be connected to the compressed-air source 6 via a pressure-adjusting element 8. The fresh powder line 16 and / or 18 may be fluidly connected at its upstream end, either directly or through the powder pump 4, to a powder delivery tube 70 which is submerged in the supplier vessel 12 or 14 for aspiration of fresh coating powder. The powder pump 4 may be at the beginning, at the end or in between in the fresh powder line 16 18 or at the upper or lower end of the powder delivery tube 70 are arranged.

FIG. 1 shows, as a fresh powder small container, a fresh powder powder bag 12 in a bag receiving hopper 74. The powder bag 12 is held in a defined shape by the bag receiving hopper 74, the bag opening being located at the upper bag end. The bag receiving hopper 74 may be disposed on a scale or weighing sensors 76. Depending on the type, this balance or the weighing sensors can produce a visual display and / or an electrical signal which, after subtracting the weight of the bag receiving hopper 74, corresponds to the weight and thus also the quantity of the coating powder in the small container 12. At the bag receiving hopper 74, at least one vibrator 78 vibrating it is preferably arranged. It is essential that in the powder spray coating system as shown in FIG. 1, the powder portion separated from the suction air flow in the cyclone separator 100 can be fed directly from the cyclone separator 100 via the powder recovery line 50 to the intermediate tank chamber 22 by means of a powder pump 4 without being en route from the powder collecting area 104 of the cyclone 100 to the buffer tank 22 the recovery powder must pass through a sieve device, for example the sieve device 10. This is possible because a sieve for sieving the powder deposited in the separation region 103 of the cyclone separator 100 can already be provided inside the cyclone separator. Of course, it is also possible that, despite a sieve provided in the cyclone separator 100, the powder fraction separated from the suction air flow in the cyclone separator 100 is first conducted into the sieve device and from there into the intermediate container chamber 22 by means of the powder pump 4 as recovery powder. Hereinafter, a cyclone separator 100 according to an embodiment of the invention with reference to the illustration of FIG. 2 described in more detail. In this case, FIG. Figure 2 is a longitudinal sectional view of a plan view of the lower end portion of the cyclone separator according to an embodiment of the invention. According to the illustrated embodiment of the cyclone separator 100 according to the invention, at least the lower end region 103a of the separating region 103 is embodied in the manner of a truncated cone with a jacket geometry which tapers in the direction of the powder collecting region 104, in particular tapered. Although in FIG. 2, the upper end region 103b of the separating region 103 can likewise be slightly conically tapered or else cylindrical, as shown in the illustration of the cyclone separator 100 in FIG. 1 is indicated.

At the upper end of the separation region 103, a likewise cylindrically formed inlet region 101 adjoins the powder inlet 101. In the radial center of the inlet region there is an airflow outlet, which is formed by the upstream end of the exhaust air line 54 or to which the exhaust air line 54 may be connected.

For collecting the powder deposited in the separation region 103, the powder collection region 104 is connected or connectable to the lower end region 103a of the deposition region 103. In the embodiment according to FIG. 2, the lower end portion 103a of the separation portion 103 is connected to the powder collecting portion 104 via a cylindrical screen case 120 in which the screen 121 is held.

The powder collecting region 104 has a powder discharge 105, in particular a conically tapering casing geometry, which is directed towards the lower end of the powder collecting region 104, so that the recycling powder collected in the powder collecting region 104 falls by gravity into the powder outlet 105. The powder outlet 105 is provided with the powder outlet valve 64, preferably a pinch valve, by means of which the powder outlet 105 can be alternately opened or closed.

In the lower part of the powder collecting area 104, a fluidizing device 66 may be arranged to fluidize the recovery powder in the powder collecting area 104. The fluidizing device 66 may enter the powder collecting area 104 protrude or preferably be formed such that the fluidizing wall 66 at least a portion of the wall of the powder collecting area 104th

The term fluidizing here means that the fluidizing compressed air flows through the recovery powder and thereby sets the recovery powder in a flowable (fluidized) state or improves the flowability of the recovery powder.

As already indicated, the powder collecting region 104 can be provided with at least one sensor S3. This may be a level sensor or switch which generates a signal depending on whether or not the recovery powder in the powder collection area 104 reaches at least the powder level detected by the sensor S3. For example, the sensor S3 is located a certain distance above the powder outlet valve 64 and may be used to define a predetermined reserve amount of recovery powder.

The use of at least one sensor S3 allows control of the powder outlet valve 64 in response to a signal from the sensor S3 by means of the controller 3. The powder outlet valve 64 may be controlled by the controller 3, if desired, also depending on other criteria, for example depending on whether the sensor Sl of the intermediate container 24 reports powder requirement and / or depending on the sensors or weighing cells 76 and thus depending on whether enough fresh powder in the fresh powder container 12 is present or not.

It is preferable if a means for generating mechanical vibrations is provided in the powder collecting area 104, so that mechanical vibration can be applied to the powder collecting area 104 if necessary, thereby releasing powder material deposited on the sensor S3, if necessary. The powder outlet valve 64 is preferably opened only when recovery powder is withdrawn from the powder collecting area 104, while the powder outlet valve 64 is preferably always closed when no powder is taken out from the cyclone 100 and the powder collecting area 104, respectively. This avoids that air gets into the cyclone 100 and disturbs the centrifugal separation.

According to the preferred embodiment shown in the drawings, the powder recovery line 50 is connected to the outlet side of the powder outlet valve 64. Preferably, in the powder recovery line 50, or more preferably at its upstream or downstream end, is a powder pump 4 for pumping recovery powder from the powder collection area 104 to the tundish chamber 22. According to a preferred embodiment of the invention, this powder pump 4 is controlled by a controller 3 are only switched on when the powder outlet valve 64 is opened by the control unit 3. Depending on the type of powder pump 4, this prevents compressed air from being sucked out of the cyclone separator 100 or being conveyed into the cyclone separator 100, thereby disturbing the function of the cyclone separator 100.

In the case of FIG. 2 partly shown cyclone separator 100 is provided, that on the one hand the lower end portion 103a of the Abscheidebereiches 103 is truncated with a tapered in the direction of the powder collecting 104, in particular tapered shell geometry is executed, and on the other hand, the powder collection area 104 also with a in The generatrices M l, M2 of the frustoconical lower end portion 103a of the Abscheidebereiches 103 and the generatrices M3, M4 of the cally formed powder collecting 104 each at least approximately at the same angle to the longitudinal axis of the Cyclone separator 100 may have.

Between the lower end portion 103a of the deposition portion 103 and the powder collecting portion 104 is a cylindrical intermediate portion which is formed by the screen housing 120 in the illustrated embodiment of the cyclone 100. This screen case 120 serves to hold the screen 121, and is preferably insertable into the space between the lower end portion 103a of the separation portion 103 and the powder collecting portion 104, that is, it is possible to hold the screen 121. H. removably arranged.

The cyclone separator 100 according to the invention is characterized in that at least the inner surface of the inlet region 101 which comes into contact with the powder-air mixture stream and / or at least the inner surface of the precipitation region 103 which comes into contact with the powder-air mixture stream at least in places made of a special hard and thus resistant material which has a Rockwell hardness C (Rc) of at least 60. It is also conceivable in this context if the inner surface of the truncated cone-shaped end region 103a of the deposition region 103 is at least partially made of the said hard material, at least in regions.

In particular, a hard metal, a hard metal alloy, a metal carbide or a ceramic material, in particular an enamel, are suitable for the hard material. It is conceivable in this context to design the inner surface of the area, which is made of the hard material, as an integral part of the cyclone separator 100, or as a coating or as an insert.

In particular, a ceramic material in the sense of the present invention also denotes a mass of inorganic composition, mostly consisting of silicates and oxides, which is produced in most glassy solidified form by melting or frying, which means a melting process that is interrupted shortly before completion. This mass is applied, usually with additives, usually in one or more layers on a carrier material and melted at high temperatures and short burning time, which is usually a coating of the carrier material is desired. Email is used on metal or glass as a carrier material.

According to some embodiments of the invention, the term "enamel" used herein corresponds to an "enamel lacquer" or an "enamel paste". The invention is not limited to the embodiments of the cyclone separator according to the invention shown by way of example in the drawings, but rather results from a general expert consideration of the patent claims and the description, in particular of the exemplary embodiments.

Claims

CYCLONE

claims

A cyclone separator (100), in particular for a powder recovery device in an enamel powder coating plant, the cyclone separator (100) comprising:

an inlet region (101) having a powder inlet (102) for a powder-air mixture stream;

one at the lower end of the inlet region (101) subsequent

Separation region (103) for centrifugal separation of at least one

Part of the powder contained in the mixture stream;

one with the lower end portion (103a) of the deposition area

(103) connected or connectable powder collection area (104) for

Collecting the powder deposited in the separation region (103); and

a dip tube opening out from above into the inlet region (101) for removing air from the mixture stream,

d a d u r c h e s e n c i n e s, d a s s

at least the inner surface of the inlet region (101) which comes into contact with the powder-air mixture stream and / or at least the inner surface of the separation region (103) which comes into contact with the powder-air mixture stream is made, at least in regions, from a material which is a Rockwell Hardness C (Rc) of at least 60.

2. cyclone separator (100) according to claim 1,

wherein the lower end region (103a) of the deposition region (103) is frusto-conical with a tapered, in particular tapered, shell geometry in the direction of the powder collection region (104), wherein in particular the inner surface of the frustoconical end region of the deposition region (103) is at least in regions made of material having a Rockwell hardness C (Rc) of at least 60.

3. cyclone separator (100) according to claim 1 or 2,

wherein the material having a Rockwell hardness C (Rc) of at least 60 comprises a cemented carbide, a cemented carbide alloy, a metal carbide, a ceramic material, in particular an enamel, a nitride, boride, oxide and / or diamond.

4. cyclone separator (100) according to any one of claims 1 to 3,

wherein the material having a Rockwell hardness C (Rc) of at least 60 comprises tungsten carbide, titanium carbide, chromium carbide, boron carbide and / or iron carbide.

5. cyclone separator (100) according to any one of claims 1 to 4,

wherein the region of the inner surface made of the material having a Rockwell hardness C (Rc) of at least 60 is an integral part of the cyclone separator (100), a coating or an insert.

6. cyclone separator (100) according to any one of claims 1 to 5,

wherein the region of the inner surface, which is made of the material having a Rockwell hardness C (Rc) of at least 60, at least partially surface-treated, in particular scrubbed, ground, and / or polished, in particular such that the inner surface at least partially a roughness (Ra) of <0.20 μιτι and preferably a roughness (Ra) of <0.12 μιτι has.

A cyclone separator (100) according to any one of claims 1 to 6, wherein a fluidizing device (66) is provided for fluidising powder collected as a reclaiming powder in the powder collecting area (104).

8. cyclone separator (100) according to claim 7,

wherein the fluidizing device (66) has at least one fluidizing wall (80) between a wall of the powder collecting area (104) and a fluidizing compressed air chamber (81), and wherein the fluidizing wall (80) has a plurality of open pores or bores which are so small in that they are permeable to fluidizing air but impermeable to powder particles of the recovery powder.

9. cyclone separator (100) according to claim 8,

wherein the at least one fluidizing wall (80) forms at least a portion of a wall forming the powder collecting area (104).

10. cyclone separator (100) according to any one of claims 1 to 9,

wherein the powder collecting portion (104) has at its lower end a powder outlet (105) for discharging the powder collected in the powder collecting portion (104), and the powder outlet (105) is provided with a powder outlet valve (64) so that when the Pulverauslassventil (64) is closed, in the powder collecting region (104) in the deposition region (103) deposited powder is stored as recovery powder.

11. cyclone separator (100) according to claim 8,

wherein the powder outlet valve (64) is designed as a pinch valve.

12. cyclone separator (100) according to any one of claims 1 to 11,

wherein the powder collecting area (104) is provided with at least one sensor (S3) for detecting at least a predetermined powder level in the powder collecting area (104).

13. cyclone separator (100) according to claim 12,

wherein means for generating mechanical vibrations is provided in the powder collecting area (104).

14. cyclone separator (100) according to claim 10 or 11 and 12 or 13,

wherein a control device (3) is provided which is connected in terms of control with the at least one sensor (S3) and with the powder outlet valve (64) and which is designed to control the powder outlet valve (64) in dependence on at least one signal of the at least one sensor ( S3).

15. A powder recovery device, in particular for an enamel powder coating plant, wherein the powder recovery device comprises a cyclone separator (100) according to one of claims 1 to 14, which at the lower end of the powder collecting region (104) comprises a powder outlet (105) with a powder outlet valve (64) for discharging the powder collected in the powder collecting section (104), and further comprising a powder pump (4) downstream of the powder outlet valve in a powder outlet path for conveying powder collected as recovery powder from the powder collecting section (104).