Screening device for separating visible material into a fine material, screening system and method for operating a screening device

Abstract

The present invention provides a classifier (10), in particular a high-performance air classifier, for separating material into fines and coarses. The classifier (10) comprises: a stationary machine housing (11) having a coarse discharge (12); a static guide vane basket (13) arranged in the machine housing (11), which has a guide vane ring formed from a plurality of pivotable flap devices (14); and wherein the guide vane ring further comprises a nozzle flap device (15) configured to convey a purge gas flow in the direction of the coarse discharge (12). The present invention also provides a classifier system (1) with such a classifier (10) and a method (M) for operating such a classifier.

Description

[0001] The present invention relates to a classifier, in particular a high-performance air classifier, for separating material into fines and coarses. The present invention further relates to a classifier system with such a classifier and to a method for operating a classifier.

[0002] Typically, air classifiers, such as the one described in DE 44 18 195 A1, are operated by feeding material to be classified, also referred to as the material to be classified, via a product feed line. This material is then fed between a static guide vane basket and a classifier wheel located inside the guide vane basket by means of a metering screw or similar device. The guide vane basket and the classifier wheel are housed in a classifier casing. An operating medium in the form of classifying gas / vapor is introduced between the classifier casing and the guide vane basket via an operating medium supply line and flows through the static guide vane basket. On the inside of the guide vane basket, the material to be classified is intensively permeated by the operating medium, dispersed, and transported to the classifier wheel for separation. The coarse material then passes through a rear classifying chamber defined by an orifice plate in a helical motion to the coarse material outlet.

[0003] Such air classifiers are often installed downstream of a mill, dryer, or other process equipment. Downstream of this equipment, the material to be classified is usually dispersed in a gas or steam stream, or more generally, a fluid stream. To perform the classification process described above, the material to be classified must be separated from the fluid stream by means of a filter.

[0004] When classifying products, especially those that adhere to surfaces, the coarse material outlet of the classifier can become clogged. This is particularly common when used in a classification process for hygroscopic products. For this situation, purging methods are known that heat a purge gas to at least 100 °C to prevent condensation or partial cooling.

[0005] The object of the present invention is to provide a classifier device and a method for operating a classifier device that facilitates rinsing of the coarse material discharge and functions reliably so that no blockage occurs.

[0006] According to the invention, this problem is solved in each case by the subject matter of the independent claims.

[0007] According to a first aspect of the invention, a classifier, in particular a high-performance air classifier, is provided for separating material into fines and coarses. The classifier comprises a stationary machine housing with a coarses outlet and a static guide vane basket arranged in the machine housing. The guide vane basket has a guide vane ring formed by a plurality of pivotable flap devices. Furthermore, the guide vane ring includes a nozzle flap device configured to direct a purge gas flow towards the coarses outlet.

[0008] According to a second aspect of the invention, a classifier system is provided. The classifier system comprises a classifier device according to the first aspect of the invention and a purge gas reservoir which stores a purge gas volume and is fluidically connected to the nozzle flap device via a supply line.

[0009] According to a third aspect of the invention, a method for operating a classifier, in particular a classifier according to the first aspect of the invention, is provided. The method comprises: Detecting a deposit in a coarse material outlet of a stationary machine housing of the classifier device, conveying a purge gas volume flow to purge the coarse material outlet using a nozzle flap device arranged in a guide vane ring.

[0010] One of the underlying ideas of the present invention is to provide a discharge aid or nozzle flap device that can be operated with a purge gas and does not interfere with the geometry of the guide vane basket. The nozzle flap device is thus integrated into the guide vane basket or guide vane; in particular, the nozzle flap device is a member of the guide vane ring. The nozzle flap device or discharge aid essentially directs the purge gas flow into the coarse material outlet.

[0011] An advantage of the present invention is that clogging of the coarse material outlet can be avoided by the nozzle flap device according to the invention. Particularly in classifier processes with hygroscopic products, the discharge or coarse material outlet can advantageously be flushed so that it does not become clogged.

[0012] Advantageous embodiments and further developments result from the dependent claims relating back to the independent claims and from the description with reference to the figures.

[0013] According to one embodiment of the present invention, the nozzle flap assembly is pivotably mounted about a pivot axis relative to the guide vane basket and is arranged closest to the coarse material outlet in relation to the plurality of pivotable flap assemblies. In particular, the nozzle flap assembly can be designed to pivot independently of the plurality of pivotable flap assemblies. However, this does not preclude the nozzle flap assembly from having a position comparable to the plurality of pivotable flap assemblies in some cases, or from being pivoted simultaneously with the plurality of pivotable flap assemblies. Thus, the nozzle flap assembly can be freely adjusted in its position for optimal application.

[0014] According to a further development of the present invention, the pivot axis of the nozzle flap assembly corresponds to a pivot axis of the plurality of pivotable flap assemblies. Furthermore, the nozzle flap assembly can have essentially the same outer contour as the plurality of pivotable flap assemblies. In some embodiments, a tapered end region can be flattened. In contrast, the tapered end region of the flap assemblies is pointed.

[0015] According to a further embodiment of the present invention, the nozzle flap assembly has a flow channel whose flow outlet is arranged in an end region of the nozzle flap assembly and whose flow inlet is connected to a supply line. In this way, the nozzle flap assembly can be supplied with the purge gas flow from outside the machine housing.

[0016] For example, the flow inlet corresponds to the pivot axis of the nozzle flap assembly. This means that the purge gas flow can enter the flow channel along the pivot axis through the flow inlet. Furthermore, the flow channel can have a curvature, a deflection, or the like, which directs the flow outlet away from the pivot axis. For example, the flow outlet can be oriented at an angle of approximately 90° relative to the flow inlet. In particular, the flow outlet can be oriented at an angle of approximately 90° relative to the pivot axis.

[0017] Furthermore, the flow outlet can be formed by several flow outlet openings, for example two or three flow outlet openings, with the flow channel branching off between the flow inlet and the flow outlet into the several flow outlet openings.

[0018] Furthermore, the classifier device can include a classifier wheel that is arranged coaxially within the guide vane ring in relation to the guide vane basket.

[0019] According to a further embodiment of the present invention, the purge gas flow rate is controlled by a control device such that the purge gas flow rate is released when a discharge flap of a rotary valve arranged in the coarse material outlet is opened. In this way, a necessary expansion volume can be ensured to prevent backflow.

[0020] According to a further embodiment of the present invention, the coarse material outlet has an opening for releasing the purge gas flow, wherein the opening is arranged and oriented such that the purge gas flow is directed towards a discharge flap of an indexing valve located in the coarse material outlet. Thus, in addition to the purge gas flow through the nozzle flap assembly, a portion of the purge gas flow can flow through the opening to the indexing valve, in particular its discharge flap. The discharge flap can be an upper or a lower discharge flap.

[0021] According to a further embodiment of the present invention, the classifier system further comprises a first valve assembly, which is integrated in the supply line upstream of the nozzle flap assembly and is configured to control the purge gas flow rate for the nozzle flap assembly. Alternatively or additionally, the first valve assembly can be integrated downstream of the temperature control device or the compressed air reservoir, or both. For example, the first valve assembly can be configured as a solenoid valve.

[0022] According to a further embodiment of the present invention, the classifier system further comprises a temperature control device integrated in the feed line upstream of the nozzle flap assembly. For example, the temperature control device can be configured to heat or cool the flow of purge gas. The temperature control device can, for example, be configured as a heating element. The temperature control device can also include a temperature control unit to regulate the flow of purge gas to a predetermined gas temperature. The predetermined gas temperature can, for example, be 100 °C or higher.

[0023] According to a further embodiment of the present invention, the classifier system further comprises a pressurized compressed air reservoir integrated in the supply line upstream of the nozzle flap assembly. The compressed air reservoir can, for example, include a bypass valve. Furthermore, the compressed air reservoir can be arranged downstream of the temperature control device.

[0024] According to a further embodiment of the present invention, the classifier system further comprises a second valve assembly, which is arranged upstream of the opening and is configured to control the purge gas flow rate for the discharge flap. The purge gas flow rate, or a portion thereof, can be diverted from the supply line. The supply line can, for example, branch off upstream of the first valve assembly, so that the nozzle flap assembly and the opening can be supplied with the purge gas flow rate independently of each other. For example, the second valve assembly can be configured as a solenoid valve.

[0025] According to a further embodiment of the present invention, the classifier system further comprises a control device that controls the first valve assembly and / or the second valve assembly such that the purge gas flow rate is released when the discharge flap is opened. This means, for example, that the control of the classifier system is timed such that a gas pulse is triggered when the upper discharge flap of the rotary valve is opened, in order to ensure the necessary expansion volume to prevent backflow.

[0026] According to a further embodiment of the present device, during the conveying of the purge gas flow rate, a first valve assembly and / or a second valve assembly is controlled such that when a discharge flap of a rotary valve arranged in the coarse material outlet is opened, the purge gas flow rate is released. The purge gas flow rate can then flow through a flow channel of the nozzle flap assembly. For example, the flow channel can be supplied via a feed line from a purge gas storage tank.

[0027] According to a further embodiment of the present invention, the method further comprises tempering the purge gas volume flow to a predetermined gas temperature before the purge gas volume flow is conveyed towards the coarse material outlet.

[0028] The inventive concept described above is expressed again below in other words. This concept relates – in simplified terms – to an adjustable discharge aid that can be operated with purge gas, and if required with hot or cold purge gas, to provide steam classification.

[0029] The above embodiments and further developments can be combined with one another as appropriate. In particular, all features of the device are transferable to the associated method, and vice versa. Further possible embodiments, further developments, and implementations of the invention also include combinations of features of the invention described previously or subsequently with respect to the exemplary embodiments, even if not explicitly mentioned. In particular, those skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the present invention.

[0030] The present invention is explained in more detail below with reference to exemplary embodiments and the accompanying figures. The figures show: Fig. 1 a schematic representation of a classifier system with a classifier device according to an embodiment of the invention; Fig. 2 a schematic front view in section of a classifier device for separating material to be classified into fine material and coarse material according to a further embodiment of the invention; Fig. 3 a schematic side view in section of the classifier device made of Fig. 2 Figs. 4A, 4B, 4C show a schematic representation of a nozzle flap device according to a further embodiment of the invention, wherein the nozzle flap device is in Fig. 4A from the front, in Fig. 4B in a cross-section and in Fig. 4C in a lateral section; and Fig. 5 a schematic flow diagram of a method for operating a classifier device according to a further embodiment of the invention.

[0031] In the figures of the drawing, identical, functionally equivalent and similarly acting elements, features and components - unless otherwise stated - are each provided with the same reference symbols.

[0032] Although specific embodiments and further developments are presented and described herein, the person skilled in the art will prefer that a multitude of alternative and / or similar embodiments can replace the specific embodiments presented and described without departing from the scope of the present invention. This application is intended to generally cover all variations or modifications of the specific embodiments described herein.

[0033] The accompanying figures are intended to provide a further understanding of embodiments of the invention and serve, in conjunction with the description, to explain the principles and concepts of the invention. Other embodiments and many of the aforementioned advantages become apparent with regard to the drawings. The drawings are to be understood merely as schematic drawings, and the elements of the drawings are not necessarily shown to scale. Directional terminology such as "above," "below," "left," "right," "over," "below," "horizontal," "vertical," "front," "back," and similar terms are used for explanatory purposes only and are not intended to limit the generality of the invention to specific embodiments as shown in the figures.

[0034] Fig. 1 Figure 1 shows a schematic representation of a classifier system 1 with a classifier device 10 according to an embodiment of the invention.

[0035] The classifier system 1 comprises a classifier device 10. The classifier device 10 is designed to separate the material to be classified into fines and coarse material. It has a stationary machine housing with a coarse material outlet 12. A static guide vane basket is arranged in the machine housing, which has a guide vane ring formed from a plurality of pivotable flap devices. The guide vane ring additionally includes a nozzle flap device 15, which is designed to convey a purge gas flow in the direction of the coarse material outlet 12.

[0036] Furthermore, the classifier system 1 includes, for example, a feed line 20, a control device 30, a first valve device 31, a second valve device 32, a purge gas accumulator 40, a temperature control device 50, and a pressurized compressed air accumulator 60.

[0037] The purge gas storage tank 40 can store a purge gas volume and be fluidically connected via the supply line 20 to the nozzle flap device 15, the first valve device 31, the second valve device 32, the purge gas storage tank 40, the temperature control device 50 and the compressed air storage tank 60.

[0038] The first valve assembly 31 can be integrated in the supply line 20 upstream of the nozzle flap assembly 15. It is designed to control the purge gas flow rate for the nozzle flap assembly 15. Alternatively or additionally, the first valve assembly 31 can be integrated downstream of the temperature control device 50 or the compressed air reservoir 60, or both. For example, the first valve assembly 31 can be designed as a solenoid valve.

[0039] The temperature control device 50 can be integrated in the supply line 20 upstream of the nozzle flap assembly 15. For example, the temperature control device 50 can be configured to heat or cool the flowing purge gas volume. The temperature control device 50 can, for example, be configured as a heating element. The temperature control device 50 can also include a temperature control unit 51 to control the flowing purge gas volume to a predetermined gas temperature. The predetermined gas temperature can, for example, be 100 °C or higher.

[0040] The compressed air reservoir 60 can be integrated in the supply line 20 upstream of the nozzle flap assembly 15. The compressed air reservoir 60 can, for example, include a bypass valve assembly 61. Furthermore, the compressed air reservoir 60 can be arranged downstream of the temperature control device 50.

[0041] Optionally, the purge gas flow rate can be controlled by the control unit 30 such that, when a discharge flap 18 of a rotary valve located in the coarse material outlet 12 is opened, the purge gas flow rate is released. Alternatively or additionally, the coarse material outlet 12 can have an opening for releasing the purge gas flow rate, the opening being arranged and oriented such that the purge gas flow rate is directed towards the discharge flap 18. Thus, in addition to the purge gas flow rate through the nozzle flap assembly 15, a portion of the purge gas flow rate can flow through the opening to the rotary valve, in particular its discharge flap 18. The discharge flap 18 can be an upper or a lower discharge flap. The control unit 30 can control the first valve assembly 31 and the second valve assembly 32 such that, when the discharge flap 18 is opened, the purge gas flow rate is released.

[0042] The second valve assembly 32 can be arranged upstream of the opening. It is designed to control the purge gas flow rate for the discharge flap 18. The purge gas flow rate, or a portion thereof, can be diverted from the supply line 20. The supply line 20 can, for example, branch off upstream of the first valve assembly 31, so that the nozzle flap assembly 15 and the opening can be supplied with the purge gas flow rate independently of each other. For example, the second valve assembly 32 can be designed as a solenoid valve.

[0043] Fig. 2 shows a schematic front view in section of a classifier device 10 for separating material to be classified into fine material and coarse material according to a further embodiment of the invention. Fig. 3 shows a schematic side view in section of the classifier device 10. Fig. 2 .

[0044] The classifier 10 is designed as an example of a high-performance air classifier and comprises a stationary machine housing 11 with a coarse material outlet 12, a static guide vane basket 13 and a guide vane ring with a plurality of pivotable flap devices 14 and with a nozzle flap device 15.

[0045] The static guide vane basket 13 is arranged in the machine housing 11. The nozzle flap assembly 15 is designed to direct a purge gas flow towards the coarse material outlet 12. That is, the nozzle flap assembly 15 essentially blows the purge gas flow into the coarse material outlet 12, as can be seen from the position and orientation of the nozzle flap assembly 15 in the figure. Fig. 2 illustrated.

[0046] Optionally, the nozzle flap assembly 15 can be pivotally mounted about a pivot axis relative to the guide vane basket 13. Furthermore, the nozzle flap assembly 15 can be arranged closest to the coarse material discharge 12 in relation to the plurality of pivotable flap assemblies 14. In particular, the nozzle flap assembly 15 can be designed to pivot independently of the plurality of pivotable flap assemblies 14. The position of the nozzle flap assembly 15 can be freely adjusted.

[0047] For example, the pivot axis of the nozzle flap assembly 15 can correspond to a pivot axis of the plurality of pivotable flap assemblies 14. Furthermore, the nozzle flap assembly 15 can have essentially the same outer contour as the plurality of pivotable flap assemblies 14.

[0048] Furthermore, the classifier device 10 can include a classifier wheel 17 which is arranged coaxially within the guide vane ring in relation to the guide vane basket 13.

[0049] Optionally, the coarse material outlet 12 can have an opening for releasing the purge gas volume flow, the opening being arranged and oriented such that the purge gas volume flow is directed onto a discharge flap 18 (see Fig. 1 ) is directed towards a timing gate arranged in the coarse material outlet 12. Thus, in addition to the purge gas volume flow through the nozzle flap device 15, a portion of the purge gas volume flow can flow through the opening to the timing gate, in particular its discharge flap 18.

[0050] Considering the exemplary classifier 10, a powdered intermediate product ZP can be fed into the classifier 10 from above via a product feeder 3. The necessary process air VL can be supplied through a classifier air inlet 2. This process air carries the powdered intermediate product ZP, fed via the product feeder 3, and guides it through a plurality of adjustable guide vane slots of the guide vane basket 13, thereby dispersing the intermediate product ZP. A protective gas, for example, can be used as the process air VL.

[0051] The intermediate product ZP, dispersed in this way, can be conveyed via the continuously variable speed classifier wheel 17, whereby the particle sizes are separated either into target and coarse material or into target and fine material. The fine particles fP exit the classifier 10 via the classifier wheel 17, which is mounted with a horizontal shaft 18 in the center of the classifier 10. The coarse particles gP are rejected by the classifier wheel 17 and discharged through the rear of the machine housing 11, which may be helically shaped, via the coarse material outlet 12 on the underside of the machine housing 11. The discharge of the coarse particles gP can be controlled by adjusting the position of the nozzle flap assembly 15 for difficult separation tasks, thus influencing the cleanliness of the coarse particles gP. The target size particles exit the classifier 10 together with the coarse material via the coarse material outlet 12.The fine particles fP were separated from the particles of the target size and therefore do not form part of the fraction which leaves the classifier 10 via the coarse material outlet 12.

[0052] The desired target particle size is regulated in particular by regulating the gas flow of the process air VL and / or the rotational speed of the classifier wheel 17. A higher gas flow and / or a lower rotational speed result in a coarser product, while a lower gas flow and / or a higher rotational speed result in a finer product.

[0053] Additionally, the Fig. 3 At least two cracking gas inlets 19 are required to purge the gap between the fines outlet and the classifier wheel 17 with a so-called cracking gas SG. However, designs with only one cracking gas inlet 19 are also possible. This purging prevents particles from becoming lodged in the classifier wheel 17 and / or the gap between the fines outlet and the classifier wheel 17, thus preventing blockage. The purging is carried out using a suitable fluid, in a preferred embodiment using a protective gas.

[0054] Fig. 4A, 4B, 4C show a schematic representation of a nozzle flap assembly 15 according to a further embodiment of the invention, wherein the nozzle flap assembly 15 is in Fig. 4A from the front, in Fig. 4B in a cross-section and in Fig. 4C shown in a side section.

[0055] As in the Figuren 4B und 4C As illustrated, the nozzle flap assembly 15 can have a flow channel 16, the flow outlet 16a of which is arranged in an end region 15a of the nozzle flap assembly 15 and the flow inlet 16b of which is connected to a supply line 20. In this way, the nozzle flap assembly 15 can be supplied with the purge gas flow from outside the machine housing 11. For example, the flow inlet 16b corresponds to the pivot axis X of the nozzle flap assembly 15.

[0056] This means that the purge gas volume flow can flow along the pivot axis X through the flow inlet 16b into the flow channel 16.

[0057] Furthermore, the flow channel may have a curvature, a deflection, or the like, whereby the flow outlet 16a is directed away from the pivot axis X. For example, the flow outlet 16a may be oriented at an angle of approximately 90° relative to the flow inlet 16b. In particular, the flow outlet 16a may be oriented at an angle of approximately 90° relative to the pivot axis X.

[0058] Furthermore, the flow outlet 16a can be formed by two flow outlet openings 16a-1, 16a-2, as shown by way of example in Fig. 4C The flow channel 16 can branch off between the flow inlet 16b and the flow outlet 16a into the two flow outlet openings 16a-1, 16a-2.

[0059] In some versions, the tapered end region 15a may be flattened. In contrast, the tapered end region of the flap devices 14 tapers to a point.

[0060] Fig. 5 Figure 1 shows a schematic flowchart of a method M for operating a classifier 10 according to a further embodiment of the invention. The classifier 10 can, for example, be constructed like the classifier made of Fig. 2 und 3 be trained.

[0061] The procedure includes, for example, the steps of detecting M1 a deposit, tempering M2 the purge gas volume flow and conveying M3 a purge gas volume flow.

[0062] In step M1, a deposit is detected in the coarse material outlet 12 of the stationary machine housing 11 of the classifier device 10.

[0063] In step M2, the purge gas volume flow is tempered to a predetermined gas temperature before the purge gas volume flow is conveyed towards the coarse material outlet 12.

[0064] In step M3, the purge gas flow rate for purging the coarse material outlet 12 is conveyed by means of the nozzle flap assembly 15 arranged in a guide vane ring. The first valve assembly 31 and / or the second valve assembly 32 can be controlled such that the purge gas flow rate is released when the discharge flap 18 of the indexing valve arranged in the coarse material outlet 12 opens. The purge gas flow rate can then flow through the flow channel 16 of the nozzle flap assembly 15. For example, the flow channel 16 can be supplied via the supply line 20 from the purge gas reservoir 40.

[0065] In the preceding detailed description, various features have been summarized in one or more examples to improve the clarity of the presentation. However, it should be clear that the above description is merely illustrative and in no way limiting. It serves to cover all alternatives, modifications, and equivalents of the various features and embodiments. Many other examples will be immediately and directly clear to the person skilled in the art based on their technical knowledge, given the above description.

[0066] The exemplary embodiments were selected and described to best illustrate the principles underlying the invention and its practical applications. This enables those skilled in the art to optimally modify and utilize the invention and its various embodiments with regard to the intended purpose. In the claims and the description, the terms "including" and "comprising" are used as neutral language terms for the corresponding terms "comprehensive." Furthermore, the use of the terms "a," "a," and "an" is not intended to fundamentally exclude multiple features and components described in this way. Bezugszeichenliste

[0067] 1 Classifier system 2 Classifier air inlet 3 Product feed 10 Classifier device 11 Machine housing 12 Coarse material outlet 13 Guide vane 14 Flap device 15 Nozzle flap device 15a Tapered end section 16 Flow channel 16a Flow outlet 16b Flow inlet 17 Classifier wheel 18 Shaft 19 Split gas supply 20 Feed line 30 Control device 31 First valve device 32 Second valve device 40 Purge gas reservoir 50 Temperature control device 51 Temperature control unit 60 Pressurized compressed air reservoir 61 Overflow valve X-swidth axis VL process air fP fine particles gP coarse particles ZPP particles of target size SG splitting gas MProcedure M1Detection of a deposit M2Temperature control M3Conveying

Claims

1. Classifier (10), in particular a high-performance air classifier, for separating material into fines and coarses, the classifier (10) comprising: a stationary machine housing (11) having a coarses outlet (12); a static guide vane basket (13) arranged in the machine housing (11) having a guide vane ring formed from a plurality of pivotable flap devices (14); and wherein the guide vane ring further comprises a nozzle flap device (15) designed to convey a purge gas volume flow in the direction of the coarses outlet (12).

2. Sifter device (10) according to claim 1, wherein the nozzle flap device (15) is pivotably mounted about a pivot axis (X) relative to the guide vane basket (13) and wherein the nozzle flap device (15) is arranged closest to the coarse material outlet (12) in relation to the plurality of pivotable flap devices (14).

3. Sifter device (10) according to claim 2, wherein the pivot axis (X) of the nozzle flap device (15) corresponds to a pivot axis of the plurality of pivotable flap devices (14).

4. Classifier device (10) according to one of the preceding claims, wherein the nozzle flap device (15) has a flow channel (16) whose flow outlet (16a) is arranged in an end region (15a) of the nozzle flap device (15) and whose flow inlet (16b) is connected to a supply line (20).

5. Classifier (10) according to one of the preceding claims, wherein the purge gas volume flow is controlled by a control device (30) such that the purge gas volume flow is released when a discharge flap (18) of a timing gate arranged in the coarse material outlet (12) is opened.

6. Classifier device (10) according to one of the preceding claims, wherein the coarse material outlet (12) has an opening for releasing the purge gas volume flow, wherein the opening is arranged and aligned such that the purge gas volume flow is directed towards a discharge flap (18) of a timing gate arranged in the coarse material outlet (12).

7. Classifier system (1) comprising: a classifier device (10) according to one of the preceding claims; and a purge gas reservoir (40) which stores a purge gas volume and is fluidically connected to the nozzle flap device (15) via a supply line (20).

8. Classifier system (1) according to claim 7, further comprising a first valve device (31) which is integrated in the supply line (20) upstream of the nozzle flap device (15) and is configured to control the purge gas volume flow for the nozzle flap device (15).

9. Classifier system (1) according to claim 7 or 8, further comprising a temperature control device (50) which is integrated in the feed line (20) upstream of the nozzle flap device (15).

10. Classifier system (1) according to one of claims 7 to 9, further comprising a pressurized compressed air reservoir (60) which is integrated in the supply line (20) upstream of the nozzle flap device (15).

11. Classifier system (1) according to claim 6 and one of claims 7 to 10, further comprising a second valve arrangement (32) which is arranged upstream of the opening and is configured to control the purge gas volume flow for the discharge flap (18).

12. Classifier system (1) according to one of claims 7 to 11, further comprising a control device (30) which controls the first valve device (31) and / or the second valve device (32) such that the purge gas volume flow is released when the discharge flap (18) is opened.

13. Method (M) for operating a classifier, in particular a classifier (10) according to any one of claims 1 to 6, comprising: detecting (M1) a deposit in a coarse material outlet (12) of a stationary machine housing (11) of the classifier (10); conveying (M3) a purge gas volume flow for purging the coarse material outlet (12) by means of a nozzle flap device (15) arranged in a guide vane ring.

14. Method (M) according to claim 13, wherein during the conveying (M3) of the purge gas volume flow, a first valve device (31) and / or a second valve device (32) is controlled such that when a discharge flap (18) of a timing gate arranged in the coarse material outlet (12) is opened, the purge gas volume flow is released.

15. Method (M) according to claim 13 or 14, further comprising: tempering (M2) the purge gas volume flow to a predetermined gas temperature before the purge gas volume flow is conveyed towards the coarse material outlet (12).

Images