Screw feeder for feeding a screw machine

Abstract

A screw feeder (28) for feeding a screw processing machine is disclosed. The screw feeder (28) comprises a housing (38) having at least one housing cavity (40) formed therein. At least one screw conveyor shaft (42) is rotatably arranged in the at least one housing cavity (40) for conveying material along a conveying direction (50) from a supply opening (48) to a feed opening (51), in which the housing (38) a vent opening (52) is formed. The vent opening (52) enables simple, fast and reliable venting and cleaning independent of the screw processing machine (28).

Description

[0001] This patent application claims priority to European patent application EP 20 214 537.1, the contents of which are incorporated herein by reference.

[0002] This invention relates to a screw feeder for feeding material into a screw processing machine. Furthermore, this invention relates to a processing apparatus having such a screw feeder and a method for operating the processing apparatus.

[0003] A processing apparatus for preparing styrene-acrylonitrile melt is disclosed in EP 3 175 967 A1. This processing apparatus includes a screw feeder laterally connected to a screw processing machine. Rubber is fed into the screw processing machine via the screw feeder.

[0004] The purpose of this invention is to construct a screw feeder for feeding screw processing machines, which can perform simple, fast and reliable cleaning.

[0005] This objective is achieved by a screw feeder for feeding a screw processing machine, the screw feeder having a housing; at least one housing cavity formed in the housing; a supply opening formed in the housing for supplying material into the at least one housing cavity; a feed opening formed in the housing for feeding material into the screw processing machine; and at least one screw conveyor shaft rotatably arranged in the at least one housing cavity for conveying material from the supply opening to the feed opening in a conveying direction, wherein a drain opening is formed in the housing. Because a drain opening is formed in the housing of the screw feeder, it is possible to drain and clean the screw feeder independently of the screw processing machine. The drain opening penetrates the housing. The drain opening connects the at least one housing cavity to the environment. For cleaning or after cleaning, material and / or cleaning agent located in the at least one housing cavity can be discharged from the at least one housing cavity through the drain opening. Therefore, it is not necessary to complexly discharge material and / or cleaning agent via the screw processing machine.

[0006] Preferably, the screw feeder is designed as a side screw feeder. A side screw feeder can be laterally connected to a screw processing machine.

[0007] Preferably, at least two interconnected housing cavities are formed within the housing. Specifically, the at least two housing cavities have a horizontal numeral 8 shape in cross-section. Preferably, the feed opening has a horizontal numeral 8 shape in cross-section. Specifically, the at least two associated screw conveyor shafts are rotatably arranged within the at least two housing cavities. Specifically, the at least two screw conveyor shafts are designed to be rotatably driveable and / or tightly meshed in the same direction.

[0008] The screw feeder includes at least one supply opening formed in the housing for supplying material. For example, the screw feeder may include multiple supply openings for supplying material components into at least one housing cavity. Features associated with the supply openings are specifically applied to the respective supply openings.

[0009] A screw feeder is configured such that a drain opening is arranged upstream of the feed opening in the conveying direction, ensuring simple, fast, and reliable cleaning. The arrangement of the drain opening ensures that material and / or cleaning agents do not need to be discharged via the screw feeder. In a first embodiment, the drain opening is arranged between and as close as possible to the feed opening, so that material and / or cleaning agents present in the screw feeder are discharged through the drain opening before being supplied to the screw feeder. In a second embodiment, the drain opening is arranged upstream of both the feed opening and the feed opening in the conveying direction.

[0010] A screw feeder is configured such that a venting opening is arranged upstream of a supply opening in the conveying direction, ensuring simple, rapid, and reliable cleaning. The venting opening is positioned upstream of both the supply and feed openings in the conveying direction, thus avoiding a location between the feed and supply openings. Therefore, the feeding of the screw feeder is never obstructed by the venting opening. For venting and / or cleaning, at least one screw conveyor shaft is rotated, causing the screw feeder to convey in a venting direction opposite to the conveying direction.

[0011] A screw feeder is configured to form a drain opening on the lower side of the housing, ensuring simple, fast, and reliable cleaning. Because the drain opening is formed on the lower side of the housing, material and / or cleaning agent can be drained by gravity. With the aid of gravity, the material and / or cleaning agent to be drained is discharged from the housing through the drain opening.

[0012] A screw feeder includes a closing element for opening and closing a drain opening, ensuring simple, quick, and reliable cleaning. The closing element allows the drain opening to be opened and closed as needed. Specifically, the closing element ensures the drain opening is tightly closed, preventing cleaning agent or liquid detergent from escaping through the drain opening. When the drain opening is closed, the screw feeder can be cleaned extremely thoroughly, for example, by alternately conveying cleaning agent in the conveying direction or the opposite draining direction. Then, to drain the cleaned contaminants and cleaning agent, the drain opening can be opened to release the contaminants and cleaning agent, allowing them to be discharged together.

[0013] A screw feeder includes a drive motor for driving at least one screw conveyor shaft to rotate in a first rotation direction and an opposite second rotation direction, ensuring simple, fast, and reliable cleaning. Because the drive motor enables the at least one screw conveyor shaft to be rotated in opposite rotation directions, particularly thorough cleaning can be achieved. In the first rotation direction, the at least one screw conveyor shaft conveys in a conveying direction, while in the second rotation direction, the at least one screw conveyor shaft conveys in an opposite emptying direction. By alternately changing the rotation direction, cleaning agent can be alternately delivered in the conveying and emptying directions, resulting in high-intensity cleaning of at least one screw conveyor shaft of the housing and / or the inner wall of the housing. The drive motor is specifically configured as an electric drive motor. Specifically, the drive motor includes motor control for setting the two opposite motor rotation directions.

[0014] A screw feeder is configured to form at least one auxiliary opening in the housing for cleaning and / or drying, ensuring simple, fast, and reliable cleaning. This at least one auxiliary opening allows a cleaning agent to be flexibly supplied into the housing or into at least one housing cavity. The cleaning agent may be in solid and / or liquid form, for example. The cleaning agent includes, for example, cleaning particles and / or cleaning liquids. Furthermore, the at least one auxiliary opening allows a desiccant, such as a drying fluid and / or a heating fluid, to be supplied and / or discharged. Preferably, the at least one auxiliary opening is formed on the upper side of the housing. Preferably, the at least one auxiliary opening is offset from the drain opening and / or supply opening in the conveying direction. For example, the at least one auxiliary opening is formed in the conveying direction between the feed opening and the supply opening and / or between the supply opening and the drain opening and / or upstream of the drain opening.

[0015] A screw feeder includes a drying device for drying the housing and / or at least one screw conveyor shaft, ensuring simple, quick, and reliable cleaning. The drying device is capable of drying at least one screw conveyor shaft and / or the inner wall of the housing after wet cleaning. Therefore, the screw feeder can be resumed operation in a simple and quick manner, enabling rapid subsequent processing of materials by a screw processing machine. Specifically, the drying device is integrated into the housing and / or in fluid communication with the housing and / or at least one housing cavity.

[0016] A screw feeder is configured such that the drying device includes a shell heater, ensuring simple, fast, and reliable cleaning. The shell heater is capable of easily and quickly drying the inner wall of the shell and / or at least one screw conveyor shaft. Specifically, the shell heater includes an electric heating element. This electric heating element is, for example, configured as a resistance heating element. The electric heating element is specifically arranged in a shell recess of the shell. The shell heater preferably includes at least one fluid channel formed in the shell. Preferably, the shell heater includes at least one fluid channel through which heating fluid can flow. The heating fluid is preferably provided by a fluid flow generator connected to the at least one fluid channel.

[0017] A screw conveyor includes a fluid flow generator for cleaning and / or drying, ensuring simple, fast, and reliable cleaning. The fluid flow generator produces a flowing fluid for drying the inner wall of at least one screw conveyor shaft and / or housing. Specifically, the fluid has a temperature higher than ambient temperature. The fluid is a liquid and / or a gas. The fluid flow generator is in communication with at least one fluid channel formed in the housing, for example. The fluid flowing through the at least one fluid channel thus heats the housing to achieve drying. The fluid flow generator is, for example, a pump. Specifically, the fluid flow generator is in communication with at least one housing cavity. For example, the fluid flow generator is connected to at least one auxiliary opening in the housing. Gas, such as air, is directed through the at least one housing cavity via the fluid flow generator, thereby drying at least one screw conveyor shaft and / or the inner wall of the housing. The gas or air is specifically heated. The fluid flow generator is, for example, configured as a compressed gas source. The fluid flow generator is specifically used to blow gas from a supply opening and into a feed hopper.

[0018] Another objective of this invention is to construct a processing apparatus capable of achieving simple, rapid, and reliable cleaning. Specifically, the processing apparatus should be able to clean in a short time.

[0019] This objective is achieved by a processing apparatus having a spiral processing machine for processing materials and a spiral feeder according to the invention for feeding the spiral processing machine. The advantages of the processing apparatus according to the invention correspond to the advantages of the spiral feeder according to the invention already described. Specifically, the processing apparatus may also be designed with at least one feature described in conjunction with the spiral feeder.

[0020] Because the spiral processing machine and the spiral feeder can be cleaned independently of each other, the spiral processing machine and / or spiral feeder can be cleaned on demand and in a time-optimized manner. Specifically, the spiral feeder does not need to be decoupled or disassembled from the spiral processing machine for evacuation and / or cleaning. When evacuating and / or cleaning, the spiral feeder is securely connected to the spiral processing machine. The spiral feeder is preferably designed as a lateral spiral feeder, which is laterally connected to the spiral processing machine.

[0021] Preferably, the spiral processing machine is designed as a multi-spindle spiral machine. The spiral processing machine includes a housing having at least one housing cavity. In the at least one housing cavity, associated processing element shafts for preparing the supplied material are rotatably arranged. Preferably, at least two housing cavities are formed in the housing, the housing cavities communicating with each other and having a horizontal numeral 8 cross-sectional shape. At least two associated processing element shafts are rotatably arranged in the at least two housing cavities and preferably rotatably driven in the same direction of rotation. The at least two processing element shafts are preferably designed to mesh tightly with each other. A material supply opening is formed in the housing, communicating with the feed opening of the spiral feeder. The material supply opening is loaded with material to be processed by the spiral feeder. Preferably, the material supply opening of the spiral processing machine is formed laterally. The material supply opening corresponds to the feed opening in cross-section.

[0022] A processing apparatus includes a control device for setting a working mode and a cleaning mode, ensuring simple, fast, and reliable cleaning. The control device enables the setting of a working mode and a cleaning mode for the processing apparatus, specifically a screw feeder and / or a screw mill. In the working mode, the screw feeder feeds material to be processed into the screw feeder. If necessary, other materials and / or at least one additive are also supplied to the screw feeder at other supply points. The material is then processed in the screw feeder. In the cleaning mode, the screw feeder and / or the screw mill are emptied and / or cleaned. Preferably, in the cleaning mode, material present in the screw feeder is discharged through an emptying opening without the material entering the screw feeder. Preferably, in the cleaning mode, the screw feeder conveys material, at least temporarily, in an emptying direction opposite to the conveying direction. For this purpose, the control device interacts with the motor control of the drive motor of the screw feeder. The cleaning mode includes, specifically, cleaning and / or drying at least one screw conveyor shaft and / or the inner wall of the screw feeder housing.

[0023] Another objective of this invention is to provide a method for operating a processing device that enables simple, fast, and reliable cleaning of a screw feeder.

[0024] This objective is achieved by a method for operating a processing apparatus, the method comprising the steps of: providing the processing apparatus and operating it in a cleaning mode, wherein in the cleaning mode, material present in the screw feeder is discharged through a venting opening, and the screw feeder is emptied. The advantages of the method according to the invention correspond to the advantages of the screw feeder and the processing apparatus according to the invention already described. Specifically, the method according to the invention may be specified to have at least one of the above-described features.

[0025] The processing apparatus operates in one working mode. In this mode, the material to be processed is fed into the screw feeder along the conveying direction via a screw feeder. In the cleaning mode, the screw feeder and the screw feeder can be emptied and / or cleaned independently of each other. Material present in the screw feeder is discharged from at least one housing cavity through a vent opening, and the screw feeder is emptied in this manner. Thus, material in the screw feeder does not enter the screw feeder in the cleaning mode. Cleaning agent supplied to the screw feeder for cleaning can also be discharged through the vent opening. There is no need to discharge cleaning agent via the screw feeder. Therefore, in the cleaning mode, the screw feeder is not separated from the screw feeder, but is securely connected to it. Preferably, the screw feeder is at least temporarily stationary in the cleaning mode.

[0026] A method designed to, at least at times, reverse the rotation direction of at least one screw conveyor shaft relative to the operating mode during a cleaning mode, ensuring simple, fast, and reliable cleaning. In the operating mode, at least one screw conveyor shaft is driven to rotate in a first rotation direction, such that material is supplied to the screw processing machine in the conveying direction. In the cleaning mode, at least one screw conveyor shaft is driven to rotate at least temporarily in a second rotation direction, opposite to the first rotation direction. Thus, material is conveyed along an emptying direction opposite to the conveying direction. Conveying along the emptying direction reliably ensures that no material enters the screw processing machine in the cleaning mode. Specifically, it ensures that material is discharged through the emptying opening. Preferably, in the cleaning mode, the at least one screw conveyor shaft is driven to rotate alternately in the first and second rotation directions. This allows the cleaning agent to be conveyed alternately between the feed opening and the emptying opening in both the conveying and emptying directions, such that the cleaning agent cleans at least one screw conveyor shaft and / or the inner wall of the housing multiple times.

[0027] One method, designed for cleaning modes, includes a drying shell and at least one screw conveyor shaft, ensuring simple, rapid, and reliable cleaning. The drying shell, or the inner wall of the shell, and / or at least one screw conveyor shaft allow for short downtime of the processing unit and rapid restart after wet cleaning. Drying is performed by a drying device. Specifically, the drying device includes a shell heater and / or a fluid flow generator.

[0028] Further features, advantages and details of the invention will become apparent from the following description of several embodiments.

[0029] Figure 1 A processing apparatus according to a first embodiment for producing a partial cross-section of a powder coating melt by means of a spiral processing machine and a spiral feeder is shown;

[0030] Figure 2 Show Figure 1 A partial cross-sectional top view of the processing device in the middle;

[0031] Figure 3 Show Figure 2 A partial cross-sectional side view of the screw feeder in the image; and

[0032] Figure 4 A partial cross-sectional view of the screw feeder according to the second embodiment is shown.

[0033] In the following text, refer to Figures 1 to 3 A first embodiment of the present invention is described. The processing apparatus 1 shown in the figures is used to prepare a powder coating premix 2 to form a powder coating melt 3. Therefore, the powder coating premix 2 represents the material to be processed.

[0034] The processing apparatus 1 includes a spiral processing machine 4 having a housing 5 composed of a plurality of housing segments 6 to 12 arranged in succession. The housing segments 6 to 12 are connected to each other to form the housing 5. Preferably, the spiral processing machine 4 is configured as a multi-axis spiral machine. Within the housing 5, two housing cavities 13 and 14 are formed, parallel to and penetrating each other, and having a horizontal numeral 8 shape in cross-section. Two processing element shafts 15 and 16 are concentrically arranged in the housing cavities 13 and 14, which can be rotated by a drive motor 17 about associated rotational axes 18 and 19. A branch gear 20 is arranged between the processing element shafts 15 and 16 and the drive motor 17. A coupling 21 is also arranged between the drive motor 17 and the branch gear 20. The processing element shafts 15 and 16 are rotated in the same direction by the drive motor 17, i.e., rotating in the same direction about the rotational axes 18 and 19.

[0035] The spiral processing machine 4 has a feeding zone 23, a plasticizing zone 24, a homogenizing zone 25 and a discharge zone 26 in sequence along the processing direction 22.

[0036] In the feed zone 23, the material to be processed is supplied to the spiral processing machine 4 in the form of powder coating premix 2. For this purpose, a material supply opening 27 is formed in the housing segment 7. The material supply opening 27 extends laterally through the housing segment 7 and into the housing cavity 14.

[0037] To feed material into the screw processing machine 4, the processing device 1 includes a screw feeder 28. The screw feeder 28 is designed as a side screw feeder. The feed screw feeder 28 is laterally connected to or attached to the housing segment 7.

[0038] In the feeding zone 23, the powder coating premix 2 is conveyed to the plasticizing zone 24. Air contained in the powder coating premix 2 is discharged through the vent opening 29. For this purpose, the vent opening 29 is formed in the housing segment 6. In the feeding zone 23, the processing element shafts 15, 16 include helical elements 30, 30', which are non-rotatably arranged on associated shafts 31, 32 and used for conveying the powder coating premix 2.

[0039] In the plasticizing zone 24, the provided powder coating premix 2 is melted. For melting, kneading elements 33, 33' are arranged on shafts 31, 32 in the plasticizing zone 24 in a rotationally fixed manner. The kneading elements 33, 33' are designed as kneading discs. Preferably, kneading blocks are arranged on shafts 31, 32 in the plasticizing zone 24 and include a plurality of kneading discs, which are integrally formed with each other.

[0040] The powder coating premix 2, plasticized or melted in the plasticizing zone 24, is conveyed to the homogenizing zone 25. In the homogenizing zone 25, the molten powder coating premix 2 or powder coating melt 3 is homogenized. In the homogenizing zone 25, kneading elements 34, 34' are arranged on shafts 31, 32 in a rotationally fixed manner. The kneading elements 34, 34' are specifically designed as kneading discs. Preferably, kneading blocks are arranged in the homogenizing zone 25, and these kneading blocks are formed by multiple kneading discs integrally connected to each other.

[0041] In discharge zone 26, the powder coating premix 3 is discharged. In discharge zone 26, spiral elements 35, 35' are arranged rotatably on shafts 31, 32 to transport the powder coating melt 3. A nozzle plate 36 is arranged on the last housing segment 12, forming a discharge opening 37.

[0042] After the powder coating melt 3 is discharged, it is cooled in a conventional manner. The cooled and cured powder coating melt 3 is then ground into powder coating powder.

[0043] The screw feeder 28 is configured as a twin-shaft side-feeding screwmachine. The screw feeder 28 includes a housing 38 having housing cavities 39 and 40 formed therein, these cavities penetrating each other and having a horizontal cross-sectional shape as shown in Figure 8. Two screw conveyor shafts 41 and 42 are concentrically arranged in the housing cavities 39 and 40, these screw conveyor shafts being driven by a drive motor 44 to rotate in the same direction about associated rotating shafts 45 and 46 via branch gears 43.

[0044] The screw feeder 28 includes a feed hopper 47 that leads to a supply opening 48. The supply opening 48 is formed on the upper side of the housing 38 and leads to housing cavities 39 and 40. Material or powder coating premix 2 is supplied into housing cavities 39 and 40 through the supply opening 48. A metering device 49 meters the material or powder coating premix 2 entering the feed hopper 47. A stirring device may be arranged in the feed hopper 47.

[0045] In the first rotational direction D1, the screw conveyor shafts 41 and 42 convey material from the supply opening 48 to the feed opening 51 in the conveying direction 50. The feed opening 51 is formed at the end of the housing 38 facing the screw processing machine 4. The feed opening 51 is formed and arranged to align with the material supply opening 27. The screw conveyor shafts 41 and 42 extend beyond the feed opening 51 and lead to the material supply opening 27. The feed opening 51 is therefore used to feed material or powder coating premix 2 into the screw processing machine 4.

[0046] The screw feeder 28 includes a vent opening 52. The vent opening 52 is formed on the lower side of the housing 38. The vent opening 52 opens into and connects the housing cavities 39 and 40 to the environment. The vent opening 52 is arranged upstream of the feed opening 51 and the supply opening 48 in the conveying direction 50. The vent opening 52 is thus positioned between the supply opening 48 and the end of the housing 38 facing the branch gear 43.

[0047] To open and close the vent opening 52, the screw feeder 28 includes a closing element 53. The closing element 53 is disposed on the housing 38. The closing element 53 is displaceable relative to the housing 38, for example, it can move linearly and / or pivot. The closing element 53 can be manually operated and / or operated by a drive not shown in detail.

[0048] To empty the screw feeder 28, the screw conveyor shafts 41 and 42 can be driven by a drive motor 44 to rotate in a second rotation direction D2, which is opposite to the first rotation direction D1. When the screw conveyor shafts 41 and 42 are driven to rotate in the second rotation direction D2, the screw feeder 28 conveys the material or powder coating premix 2 along the emptying direction 54, which is opposite to the conveying direction 50.

[0049] To provide cleaning agent R, the screw feeder 28 has an auxiliary opening 55. The auxiliary opening 55 is formed on the upper side of the housing 38. The auxiliary opening 55 is arranged to be offset from the drain opening 52 in the conveying direction 50. For example, the auxiliary opening 55 is arranged between the supply opening 48 and the drain opening 52. Alternatively or additionally, the auxiliary opening may be arranged between the supply opening 48 and the supply opening 51. To open and close the drain opening 55, the screw feeder 28 includes a closing element 63. The closing element 63 is displaceably arranged on the housing 38.

[0050] The screw feeder 28 includes a drying device 56 for drying the inner walls of the housing 38 and the screw conveyor shafts 41, 42 after wet cleaning. The drying device 56 includes a housing heater 57 having a plurality of electric heating elements 58 disposed in an associated housing recess 59. The heating elements 58 are configured, for example, as resistance heating elements.

[0051] To clean the feed hopper 47 and the supply opening 48, the screw feeder 28 includes a fluid flow generator 60. This fluid flow generator 60 is configured, for example, as a compressed gas generator. The fluid flow generator 60 is connected to the feed hopper 47. The fluid flow generator 60 can be used to dry the inner wall of the drying housing and the screw conveyor shafts 41, 42, thus being part of the drying unit 56.

[0052] The processing unit 1 includes a control device 61 for setting the operation mode and cleaning mode. The control device 61 communicates with the drive motors 17 and 44, the metering device 49, the drying device 56, the housing heater 57, and the fluid flow generator 60.

[0053] The working principle of processing device 1 is described below:

[0054] In operation, the material or powder coating premix 2 to be processed is fed to the screw feeder 28 via the metering device 49, hopper 47, and supply opening 48. The screw feeder 28 conveys the material along the conveying direction 50 to the feed opening 51. The drive motor 44 drives the screw conveyor shafts 41 and 42 in the first rotation direction D1. The material is then supplied to the housing cavities 13 and 14 of the screw processing machine 4 via the feed opening 51 and material supply opening 27.

[0055] In the spiral processing machine 4, material is conveyed from the feed zone 23 to the plasticizing zone 24 in the processing direction 22, where it is plasticized or melted. The resulting powder coating melt 3 is then conveyed to the homogenization zone 25 and homogenized there. In the discharge zone 26, the powder coating melt 3 is discharged through the discharge opening 37 and then further processed in a conventional manner.

[0056] In the event of a malfunction, such as an undesirable quality deviation or a change in the material or powder coating premix 2, the processing unit 1 must be emptied and cleaned. For this purpose, a cleaning mode is set via control device 61. In cleaning mode, the spiral processing machine 4 and the spiral feeder 28 can be emptied and cleaned independently if necessary. The emptying and cleaning of the spiral processing machine 4 is performed in a conventional manner.

[0057] The screw feeder 28 is designed to be emptied independently of the screw processor 4. For this purpose, the emptying opening 52 is opened by moving the closing element 53. The drive motor 44 drives the screw conveyor shafts 41, 42 in the second rotation direction D2, thereby conveying them in the emptying direction 54. Material present in the housing cavities 39, 40 is conveyed along the emptying direction 54 to the emptying opening 52, where it is discharged from the housing 38 or housing cavities 39, 40. Thus, the screw feeder 28 does not need to be emptied via the screw processor 4.

[0058] To clean the screw feeder 28, the feed hopper 47 and supply opening 48 are first blown out by the fluid flow generator 60. Fluid flow or pressurized gas can escape through the vent opening 52 and / or auxiliary opening 55. To clean the inner walls of the housing and the screw conveyor shafts 41, 42, the vent opening 52 is closed by the closing element 53. Subsequently, a cleaning agent R is supplied to the housing cavities 39, 40 through the auxiliary opening 55. The cleaning agent R is selected from, for example, cleaning liquids such as water or resin, and cleaning particles such as rubber particles, PP particles, or PE particles.

[0059] For cleaning, the rotation direction D1 or D2 of the screw conveyor shafts 41 and 42 is alternately changed, causing the screw conveyor shafts 41 and 42 to alternately convey along the conveying direction 50 and the venting direction 54. The cleaning agent R is thus alternately conveyed between the auxiliary opening 55 or the venting opening 52 and the feed opening 51 along the conveying direction 50 and the venting direction 54. This results in thorough cleaning of the inner wall of the housing and the screw conveyor shafts 41 and 42. After cleaning, the cleaning agent R and the cleaned contaminants are vented through the venting opening 52.

[0060] After wet cleaning, the inner walls of the housing and the screw conveyor shafts 41 and 42 are dried by the drying device 56. For this purpose, the housing heater 57 is activated, causing the electric heating element 58 to heat the housing 38 and the housing cavities 39 and 40 formed therein. The heating dries the inner walls of the housing and the screw conveyor shafts 41 and 42. Drying is aided by a fluid flow generator 60, which generates a fluid flow in the housing cavities 39 and 40. The fluid flow, or pressurized gas, flows into the housing cavities 39 and 40 through the supply opening 48 and from there into the feed opening 51, the auxiliary opening 55, and the exhaust opening 52. After drying, the screw feeder 28 is ready for reuse.

[0061] Thus, the screw feeder 28 can achieve simple, fast and reliable cleaning, and can easily and quickly restart the processing device 1 after a failure or change in materials.

[0062] Now for reference Figure 4 The second embodiment of the invention is described below. Unlike the first embodiment, the housing heater 57 includes a fluid channel 62 formed in the housing 38. To heat the housing 38, a heated fluid flow is generated in the fluid channel 62 and the housing cavities 39, 40 by a fluid flow generator 60. For this purpose, the fluid flow generator includes a fluid heater for providing heated fluid or heated liquid. For other construction and other operating principles of the processing apparatus 1, refer to the foregoing embodiments.

[0063] In summary:

[0064] The screw feeder 28 can be used to load any random material. A drain opening 52 can be formed at any location within the housing 38, as viewed along the conveying direction 50. Preferably, the drain opening 52 is formed on the lower side of the housing 38 such that material can be drained due to the attraction acting thereon. A suction device can be connected to the drain opening 52 and / or auxiliary opening 55. The auxiliary opening 55 can be formed at any random location within the housing 38. Multiple drain openings 52 and / or multiple auxiliary openings 55 can be formed within the housing 38. Cleaning agent R can be supplied via a nozzle.

Claims

1. A screw feeder for feeding a screw processing machine, having - a housing (38); - at least one housing cavity (39, 40) formed in the housing (38); - a supply opening (48) formed in the housing (38) for supplying material into the at least one housing cavity (39, 40); - a feed opening (51) formed in the housing (38) for feeding the material to the screw processing machine (4); - at least one screw conveyor shaft (41, 42) rotatably arranged in the at least one housing cavity (39, 40) for conveying the material from the supply opening (48) to the feed opening (51) along a conveying direction (50); and - a vent opening (52) formed in the housing (38); characterized in that the vent opening (52) is arranged upstream of the supply opening (48) in the conveying direction (50). the vent opening (52) is arranged upstream of the feed opening (51) in the conveying direction (50). the at least one screw conveyor shaft (41, 42) passes through the feed opening (51) and extends beyond the feed opening (51). the vent opening (52) is formed in a lower side of the housing (38). a closing element (53) is provided for opening and closing the vent opening (52). a drive motor (44) is provided for rotatingly driving the at least one screw conveyor shaft (41, 42) in a first rotational direction (D1) and in an opposite second rotational direction (D2). at least one auxiliary opening (55) is formed in the housing (38) for at least one of the group consisting of cleaning and drying. a drying device (56) is provided for drying at least one of the group consisting of the housing (38) and the at least one screw conveyor shaft (41, 42). the drying device (56) comprises a housing heater (57). a fluid flow generator (60) is provided for at least one of the group consisting of cleaning and drying.

11. A processing device having - a screw processing machine (4) for processing material; and - a screw feeder (28) for feeding the screw processing machine (4) according to claim 1. a control device (61) for setting a working mode and a cleaning mode.

13. A method for operating a processing device, comprising the steps of: - providing a processing device (1) according to claim 11; and - operating the processing device (1) in a cleaning mode, wherein in the cleaning mode material present in the screw feeder (28) is expelled through the vent opening (52) and the screw feeder (28) is vented. in the cleaning mode, at least sometimes the rotational direction (D2) of the at least one screw conveyor shaft (41, 42) is reversed relative to the working mode. the cleaning mode comprises drying at least one of the group consisting of the housing (38) and the at least one screw conveyor shaft (41, 42). ​ ​ ​ ​ ​ ​ ​ ​ ​ 2. A screw feeder according to claim 1, characterized in that ​ 3. The screw feeder of claim 1, wherein, ​ 4. The screw feeder of claim 1, wherein, ​ 5. The screw feeder of claim 1, wherein, ​ 6. The screw feeder of claim 1, wherein, ​ 7. The screw feeder of claim 1, wherein, ​ 8. The screw feeder of claim 1, wherein, ​ 9. A screw feeder as claimed in claim 8, characterized in that ​ 10. The screw feeder of claim 1, wherein, ​ ​ ​ ​ 12. The processing apparatus of claim 11, wherein, ​ ​ ​ ​ 14. The method of claim 13, wherein, ​ 15. The method of claim 13, wherein, ​

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