Active cleaning device for bracts and grains

Abstract

The utility model provides an active cleaning device for bracts and grains, which comprises a shell, an upper cleaning channel, a middle cleaning channel and a lower cleaning channel are arranged in the shell, and sieve pores are arranged at the bottom of the upper cleaning channel, the bottom of the middle cleaning channel and the bottom of the lower cleaning channel. The side face of the inlet end of the middle cleaning channel communicates with the side face of the outlet end of the upper cleaning channel, the side face of the outlet end of the middle cleaning channel communicates with the side face of the inlet end of the lower cleaning channel, and the top of the upper cleaning channel is open. And packing augers are respectively arranged in the upper cleaning channel, the middle cleaning channel and the lower cleaning channel. By the adoption of the grain cleaning and recycling device, the bracts are conveyed and primarily screened in the upper cleaning channel, then conveyed and actively cleaned in the middle cleaning channel and the lower cleaning channel in sequence, the bracts are discharged from the outlet end of the lower cleaning channel, grains carried in the bracts are completely removed, and the grain cleaning and recycling efficiency is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of bract cleaning devices, and particularly relates to an active cleaning device for bracts and grains. Background Art

[0002] The bract cleaning device is an important device on a corn harvester and is used to separate the bracts from the entrained corn grains coming from a peeling machine. Currently, the mainstream cleaning method basically adopts a screw conveyor for cleaning, and some large corn harvesters adopt a vibrating screen type grain recovery device for grain cleaning.

[0003] In the screw conveyor cleaning method, the main function of the screw conveyor is to push materials. During the cleaning process, the grains are wrapped in the bracts, and the bracts cannot be fully disturbed and dispersed, resulting in a weak grain cleaning function. After the bracts are discharged by the screw conveyor, the grains in the bracts are lost in the field. The vibrating screen type grain recovery device drives the vibrating screen surface to swing back and forth by a crank connecting rod mechanism. The bracts make an approximate linear reciprocating motion on the screen surface, and the grains in the bracts leave the bracts due to different inertia and fall into the grain recovery box through the shell-shaped screen holes on the screen surface. However, since the bracts cannot be transported away from the screen surface in time, the screen surface is easily blocked by sundries such as bracts, resulting in a large loss of corn grains. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is: how to fully separate the grains and bracts and improve the grain cleaning and recovery efficiency.

[0005] The technical solution for the utility model to solve the above technical problem is as follows:

[0006] The utility model provides an active cleaning device for bracts and grains, which includes a housing. An upper cleaning channel, a middle cleaning channel and a lower cleaning channel are arranged in the housing. Screen holes are arranged at the bottoms of the upper cleaning channel, the middle cleaning channel and the lower cleaning channel. The side of the inlet end of the middle cleaning channel is communicated with the side of the outlet end of the upper cleaning channel, and the side of the outlet end of the middle cleaning channel is communicated with the side of the inlet end of the lower cleaning channel. The top of the upper cleaning channel is open. Screw conveyors are respectively arranged in the upper cleaning channel, the middle cleaning channel and the lower cleaning channel.

[0007] The beneficial effects of the utility model are:

[0008] By adopting the present utility model, the husks are conveyed and preliminarily screened in the upper cleaning channel, and then conveyed and actively cleaned in the middle cleaning channel and the lower cleaning channel in sequence. Finally, the husks are discharged from the outlet end of the lower cleaning channel, so that the grains entrained in the husks are completely separated, effectively improving the grain cleaning and recovery efficiency. The husks are transferred twice between the upper cleaning channel, the middle cleaning channel and the lower cleaning channel, so as to shake and disperse the husks during the conveying process, reducing the tightness of the remaining grains wrapped, and making it easier to separate the grains during the subsequent screw conveyor conveying.

[0009] On the basis of the above technical solution, the present utility model can be further improved as follows.

[0010] Further, the screw conveyors are respectively an upper screw conveyor, a middle screw conveyor and a lower screw conveyor. The upper screw conveyor is located in the upper cleaning channel, the middle screw conveyor is located in the middle cleaning channel, and the lower screw conveyor is located in the lower cleaning channel. The outlet ends of the upper screw conveyor, the middle screw conveyor and the lower screw conveyor are all provided with throwing plates.

[0011] Through the throwing plates, it is convenient to apply kinetic energy to the husks at the outlet end, throw the husks into the next cleaning channel, so as to shake and disperse the husks, and making it easier to separate the grains during the subsequent screw conveyor conveying.

[0012] Further, a first slideway is provided at the bottom of the inlet end of the middle cleaning channel, and the upper end of the first slideway is connected to the bottom of the outlet end of the upper cleaning channel.

[0013] It is convenient to guide the husks to slide from the outlet end of the upper cleaning channel into the inlet end of the middle cleaning channel, improving the husk transfer efficiency.

[0014] Further, a second slideway is provided at the bottom of the outlet end of the middle cleaning channel, and the lower end of the second slideway is connected to the bottom of the inlet end of the lower cleaning channel.

[0015] It is convenient to guide the husks to slide from the outlet end of the middle cleaning channel into the inlet end of the lower cleaning channel, improving the husk transfer efficiency.

[0016] Further, one end of the throwing plate of the upper screw conveyor is connected to the blade of the upper screw conveyor.

[0017] Every time the upper screw conveyor rotates one circle, the tail of the blade of the upper screw conveyor concentrates the husks on one side of the throwing plate, and then the throwing plate throws the husks out intensively, increasing the kinetic energy of the husks, making it convenient for the husks to impact the middle screw conveyor and be fully dispersed, and making it easier to separate the grains during the subsequent conveying.

[0018] Further, two throwing plates are provided at the outlet ends of both the middle screw conveyor and the lower screw conveyor. The two throwing plates of the middle screw conveyor are evenly distributed circumferentially, and the two throwing plates of the lower screw conveyor are evenly distributed circumferentially.

[0019] The middle auger and the lower auger can convey the bracts once every half turn. The middle auger fully scatters and conveys the bracts, making it easier to separate the grains during subsequent conveying. At the same time, the lower auger can timely discharge the bracts conveyed to the outlet end, avoiding blockage.

[0020] Further, blade areas are respectively provided at the inlet ends of the middle auger and the lower auger, and cleaning areas are respectively provided in the middle parts of the middle auger and the lower auger. Two rows of first grain separating columns and two rows of second grain separating columns are distributed on the surface of the cleaning area. The first grain separating columns and the second grain separating columns are both arranged along the axial direction of the cleaning area. The first grain separating columns and the second grain separating columns are axially staggered with each other in the cleaning area, and the first grain separating columns and the second grain separating columns are circumferentially staggered with each other in the cleaning area.

[0021] In the blade area, the bracts are quickly pushed forward by the blades to avoid material blockage at the inlet. In the cleaning area, the bracts are lifted by the powder grain columns to facilitate full scattering of the bracts, so as to fully separate the grains. The first grain separating columns and the second grain separating columns successively deflect the bracts, so that the bracts can move towards the outlet end, ensuring the conveying efficiency.

[0022] Further, part of the cleaning area coincides with the blade area.

[0023] Through the powder grain columns at the overlapping part, it is convenient to break up the bracts, avoiding an increase in pushing resistance caused by the bracts agglomerating, and ensuring that the blade area can push the bracts to the cleaning area.

[0024] Further, two oppositely arranged inclined guide plates are also provided on the housing. The two inclined guide plates and the opposite side walls of the housing enclose a funnel shape. The lower ends of the two inclined guide plates are respectively connected to the tops of the two side walls of the upper cleaning channel. The upper cleaning channel is located in the middle of the housing, and the lower cleaning channel is located at the edge of the housing.

[0025] It is convenient to guide the bracts dropped by the peeling machine into the upper cleaning channel, avoiding the accumulation and retention of the bracts. The upper cleaning channel is located in the middle of the housing, facilitating the uniform falling of the bracts into the upper cleaning channel. The lower cleaning channel is located at the edge of the housing, avoiding the obstruction of the physical structure of the device to the discharge of the bracts and facilitating the cleaning of the bracts.

[0026] Further, the bottoms of the upper cleaning channel, the middle cleaning channel, and the lower cleaning channel are all semi-cylindrical. The bottom of the outlet end of the lower cleaning channel is open.

[0027] By matching the semi-cylindrical bottom wall with the auger, dead corners are eliminated, avoiding bract jamming. When the bracts are conveyed to the outlet end of the lower cleaning channel, they are discharged from the bottom, improving the discharge efficiency. Description of the Drawings

[0028] Figure 1 It is a structural schematic diagram of the present utility model.

[0029] Figure 2 This is a schematic diagram of the internal structure of the present utility model.

[0030] Figure 3 This is a detailed structure diagram of the cleaning channel.

[0031] Figure 4 is Figure 3 A front view along the axial direction of the auger.

[0032] In the drawings, the technical features represented by the reference numerals are as follows:

[0033] 1 - housing; 2 - upper cleaning channel; 3 - middle cleaning channel; 4 - lower cleaning channel; 5 - upper auger; 6 - middle auger; 7 - lower auger; 8 - throwing plate; 9 - first slideway; 10 - second slideway; 11 - first particle separation column; 12 - second particle separation column; 13 - inclined guide plate. Specific embodiments

[0034] The principles and features of the present utility model will be described below. The examples given are only for explaining the present utility model and are not intended to limit the scope of the present utility model.

[0035] The present utility model is referred to Figures 1-4 .

[0036] The present utility model provides an active cleaning device for bracts and grains, including a housing 1. An upper cleaning channel 2, a middle cleaning channel 3 and a lower cleaning channel 4 are arranged in the housing 1. Sieve holes are arranged at the bottoms of the upper cleaning channel 2, the middle cleaning channel 3 and the lower cleaning channel 4. The side of the inlet end of the middle cleaning channel 3 communicates with the side of the outlet end of the upper cleaning channel 2, and the side of the outlet end of the middle cleaning channel 3 communicates with the side of the inlet end of the lower cleaning channel 4. The top of the upper cleaning channel 2 is open. Augers are respectively arranged in the upper cleaning channel 2, the middle cleaning channel 3 and the lower cleaning channel 4.

[0037] Principle:

[0038] The augers in the upper cleaning channel 2, the middle cleaning channel 3 and the lower cleaning channel 4 are all rotatably connected to the housing 1, and one end of each of them extends out of the housing 1 for obtaining power through a sprocket mechanism to connect a driving device. During installation, the housing 1 is arranged below the outlet of the peeling machine of the harvester, and the top opening of the upper cleaning channel 2 faces the outlet of the peeling machine.

[0039] During operation, the husks from the outlet of the peeling machine fall into the upper cleaning channel 2. The upper auger 5 inside the upper cleaning channel 2 sends the husks to the outlet end of the upper cleaning channel 2. Subsequently, the husks fall from the outlet end of the upper cleaning channel 2 into the inlet end of the middle cleaning channel 3. The middle auger 6 inside the middle cleaning channel 3 then sends the husks to the outlet end. Then the husks fall from the outlet end of the middle cleaning channel 3 into the inlet end of the lower cleaning channel 4. The lower auger 7 inside the lower cleaning channel 4 finally sends the husks to the outlet end of the lower cleaning channel 4 to discharge the husks from the device. During the process of the auger transporting the husks, the husks are continuously flipped, so that the entrained grains are separated and fall out from the sieve holes at the bottom of the upper cleaning channel 2, the middle cleaning channel 3 or the lower cleaning channel 4. The husks are transferred twice between the upper cleaning channel 2, the middle cleaning channel 3 and the lower cleaning channel 4, so that the husks are shaken loose twice during the transportation process, reducing the tightness of the remaining grains wrapped, and it is easier to separate the grains during the subsequent auger transportation.

[0040] In summary, by adopting the present utility model, the husks are transported and initially screened in the upper cleaning channel 2, and then transported and actively cleaned in the middle cleaning channel 3 and the lower cleaning channel 4 in sequence, and finally the husks are discharged from the outlet end of the lower cleaning channel 4, so that the grains entrained in the husks are completely removed, effectively improving the grain cleaning and recovery efficiency; the husks are transferred twice between the upper cleaning channel 2, the middle cleaning channel 3 and the lower cleaning channel 4, so as to shake loose the husks during the transportation process, reducing the tightness of the remaining grains wrapped, and it is easier to separate the grains during the subsequent auger transportation.

[0041] Further, the augers are respectively an upper auger 5, a middle auger 6 and a lower auger 7. The upper auger 5 is located inside the upper cleaning channel 2, the middle auger 6 is located inside the middle cleaning channel 3, and the lower auger 7 is located inside the lower cleaning channel 4; throwing plates 8 are provided at the outlet ends of the upper auger 5, the middle auger 6 and the lower auger 7.

[0042] Note: The outlet end of the upper auger 5 and the outlet end of the upper cleaning channel 2 are the ends with the same orientation. The outlet end of the middle auger 6 and the outlet end of the middle cleaning channel 3 are the ends with the same orientation. The outlet end of the lower auger 7 and the outlet end of the lower cleaning channel 4 are the ends with the same orientation.

[0043] Through the throwing plate 8, it is convenient to apply kinetic energy to the husks at the outlet end, throw the husks into the next cleaning channel, so as to shake loose the husks, and it is easier to separate the grains during the subsequent auger transportation.

[0044] Further, as Figures 3-4 shown: A first slideway 9 is provided at the bottom of the inlet end of the middle cleaning channel 3, and the upper end of the first slideway 9 is connected to the bottom of the outlet end of the upper cleaning channel 2.

[0045] It is convenient to guide the bracts to slide into the inlet end of the middle cleaning channel 3 from the outlet end of the upper cleaning channel 2, improving the transfer efficiency of the bracts.

[0046] Furthermore, a second slideway 10 is provided at the bottom of the outlet end of the middle cleaning channel 3, and the lower end of the second slideway 10 is connected to the bottom of the inlet end of the lower cleaning channel 4.

[0047] It is convenient to guide the bracts to slide into the inlet end of the lower cleaning channel 4 from the outlet end of the middle cleaning channel 3, improving the transfer efficiency of the bracts.

[0048] Furthermore, one end of the throwing plate 8 of the upper auger 5 is connected to the blade of the upper auger 5.

[0049] Every time the upper auger 5 rotates one circle, the tail of the blade of the upper auger 5 concentrates the bracts on one side of the throwing plate 8, and then the throwing plate 8 throws the bracts out concentratedly, increasing the kinetic energy of the bracts, facilitating the impact of the bracts on the middle auger 6 and fully dispersing them, and making it easier to separate the grains during subsequent conveying.

[0050] Furthermore, two throwing plates 8 are provided at the outlet ends of both the middle auger 6 and the lower auger 7. The two throwing plates 8 of the middle auger 6 are evenly distributed circumferentially, and the two throwing plates 8 of the lower auger 7 are evenly distributed circumferentially.

[0051] The middle auger 6 and the lower auger 7 can throw the bracts once every half turn of rotation. The middle auger 6 fully disperses and throws the bracts, making it easier to separate the grains during subsequent conveying; at the same time, the lower auger 7 can timely discharge the bracts conveyed to the outlet end, avoiding blockage.

[0052] Furthermore, blade areas are respectively provided at the inlet ends of the middle auger 6 and the lower auger 7, and cleaning areas are respectively provided in the middle parts of the middle auger 6 and the lower auger 7. Two rows of first grain separating columns 11 and two rows of second grain separating columns 12 are distributed on the surface of the cleaning area. The first grain separating columns 11 and the second grain separating columns 12 are both arranged along the axial direction of the cleaning area. The first grain separating columns 11 and the second grain separating columns 12 are axially staggered with each other in the cleaning area, and the first grain separating columns 11 and the second grain separating columns 12 are circumferentially staggered with each other in the cleaning area.

[0053] In the blade area, the bracts are quickly pushed forward by the blades to avoid material blockage at the inlet; in the cleaning area, the bracts are lifted by the powder grain columns to facilitate full dispersion of the bracts, so as to fully separate the grains; the first grain separating columns 11 and the second grain separating columns 12 sequentially push the bracts, so that the bracts can move towards the outlet end, ensuring the conveying efficiency.

[0054] Furthermore, part of the cleaning area coincides with the blade area.

[0055] Note: At the overlapping part, there are both blades, the first particle separating column 11 and the second particle separating column 12. The blade passes through the gap between the first particle separating column 11 and the second particle separating column 12.

[0056] The powder particle column at the overlapping part facilitates the separation of the husks, avoiding the increase in pushing resistance caused by the agglomeration of the husks and ensuring that the blade area can push the husks to the cleaning area.

[0057] Furthermore, as Figure 1 shown: There are also two oppositely arranged inclined guide plates 13 on the housing 1. The two inclined guide plates 13 and the opposite side walls of the housing 1 enclose a funnel shape. The lower ends of the two inclined guide plates 13 are respectively connected to the tops of the two side walls of the upper cleaning channel 2. The upper cleaning channel 2 is located in the middle of the housing 1, and the lower cleaning channel 4 is located at the edge of the housing 1.

[0058] This facilitates guiding the husks dropped by the peeling machine into the upper cleaning channel 2, avoiding the accumulation and retention of the husks. The upper cleaning channel 2 is located in the middle of the housing 1, facilitating the even falling of the husks into the upper cleaning channel 2. The lower cleaning channel 4 is located at the edge of the housing 1, avoiding the obstruction of the physical structure of the device to the discharge of the husks and facilitating the cleaning of the husks.

[0059] Furthermore, the bottoms of the upper cleaning channel 2, the middle cleaning channel 3, and the lower cleaning channel 4 are all semi-cylindrical. The bottom of the outlet end of the lower cleaning channel 4 is open.

[0060] The cooperation between the semi-cylindrical bottom wall and the auger eliminates dead corners and avoids the jamming of the husks. When the husks are transported to the outlet end of the lower cleaning channel 4, they are discharged from the bottom, improving the discharge efficiency.

[0061] In the description of the present invention, it should be understood that if descriptive terms indicating orientation, direction, or positional relationship appear, such as: "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated in this specification is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of understanding the present invention and simplifying the description, rather than indicating or implying that the part, component, or whole referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0062] In addition, if ordinal description terms such as "first", "second", etc. appear, their use in this specification is for the convenience of understanding or simplifying the description. For example, in order to distinguish multiple technical features of the same type or function when it is necessary to mention them separately, this specification may use the method of prefixing or suffixing ordinal description terms to distinguish them. Therefore, it should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present utility model, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0063] In the present utility model, if structural relative action relationship description terms such as "mounted", "connected", "joined", "fixed", etc. are used, unless otherwise clearly specified and defined, they should be understood in a broad sense. For example, "mounted", "connected", "joined", etc. can be a fixed connection, a detachable connection, or integrated; can be a mechanical connection or an electrical connection; can be directly connected or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements; "fixed" can be fixed as an integral body or fixed detachably through fasteners; can be directly fixed or fixed through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above description terms in the present utility model can be understood according to the specific circumstances, the context, the coherence of the context before and after, etc.

[0064] In the present utility model, if description terms containing an affiliated or connection meaning appear, for example, the first feature is "on" or "under" the second feature, unless otherwise clearly specified and defined, it should not be understood in a restrictive sense. For example, "on" or "under" can be that the first and second features are in direct contact, or that the first feature and the second feature are in indirect contact through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above description terms in the present utility model can be understood according to the specific circumstances, the context, the coherence of the context before and after, etc.

[0065] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments, examples, and the features of different embodiments and examples described in this specification, and these combinations or combinations should fall within the scope summarized by the present utility model.

[0066] Although the embodiments of the present utility model have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limitations on the present utility model. Within the scope of information available to those of ordinary skill in the art through public channels, with the technical inspiration given in this application document, the changes, modifications, substitutions, and variations made to the above embodiments can still be covered by the protection scope of this application.

Claims

1. An active cleaning device for bracts and grains, characterized in that: It includes a housing (1), and an upper cleaning channel (2), a middle cleaning channel (3) and a lower cleaning channel (4) are provided inside the housing (1). Sieve holes are provided at the bottoms of the upper cleaning channel (2), the middle cleaning channel (3) and the lower cleaning channel (4); the side of the inlet end of the middle cleaning channel (3) communicates with the side of the outlet end of the upper cleaning channel (2), and the side of the outlet end of the middle cleaning channel (3) communicates with the side of the inlet end of the lower cleaning channel (4). The top of the upper cleaning channel (2) is open; augers are respectively provided inside the upper cleaning channel (2), the middle cleaning channel (3) and the lower cleaning channel (4).

2. The active cleaning device for bracts and grains according to claim 1, wherein: The augers are respectively an upper auger (5), a middle auger (6) and a lower auger (7). The upper auger (5) is located inside the upper cleaning channel (2), the middle auger (6) is located inside the middle cleaning channel (3), and the lower auger (7) is located inside the lower cleaning channel (4); throwing plates (8) are provided at the outlet ends of the upper auger (5), the middle auger (6) and the lower auger (7).

3. The active cleaning device for bracts and grains according to claim 2, wherein: A first slideway (9) is provided at the bottom of the inlet end of the middle cleaning channel (3), and the upper end of the first slideway (9) is connected to the bottom of the outlet end of the upper cleaning channel (2).

4. The active cleaning device for bracts and grains according to claim 3, characterized in that: A second slideway (10) is provided at the bottom of the outlet end of the middle cleaning channel (3), and the lower end of the second slideway (10) is connected to the bottom of the inlet end of the lower cleaning channel (4).

5. The active cleaning device for bracts and grains according to claim 2, characterized in that: One end of the throwing plate (8) of the upper auger (5) is connected to the blade of the upper auger (5).

6. The active cleaning device for bracts and grains according to claim 2, characterized in that: Two throwing plates (8) are provided at the outlet ends of the middle auger (6) and the lower auger (7). The two throwing plates (8) of the middle auger (6) are evenly distributed along the circumferential direction, and the two throwing plates (8) of the lower auger (7) are evenly distributed along the circumferential direction.

7. The active cleaning device for bracts and grains according to claim 6, wherein: Blade areas are respectively provided at the inlet ends of the middle auger (6) and the lower auger (7), and cleaning areas are respectively provided in the middle parts of the middle auger (6) and the lower auger (7). Two rows of first particle separating columns (11) and two rows of second particle separating columns (12) are distributed on the surface of the cleaning area. The first particle separating columns (11) and the second particle separating columns (12) are arranged along the axial direction of the cleaning area. The first particle separating columns (11) and the second particle separating columns (12) are axially staggered with each other in the cleaning area, and the first particle separating columns (11) and the second particle separating columns (12) are circumferentially staggered with each other in the cleaning area.

8. The active cleaning device for bracts and grains according to claim 7, characterized in that: The cleaning area partially overlaps with the blade area.

9. The active cleaning device for bracts and grains according to claim 1, characterized in that: Two oppositely arranged inclined guide plates (13) are further provided on the housing (1). The two inclined guide plates (13) and the opposite side walls of the housing (1) enclose a funnel shape. The lower ends of the two inclined guide plates (13) are respectively connected to the top of the two side walls of the upper cleaning channel (2); the upper cleaning channel (2) is located in the middle of the housing (1), and the lower cleaning channel (4) is located at the edge of the housing (1).

10. The active cleaning device for bracts and grains according to claim 1, characterized in that: The bottoms of the upper cleaning channel (2), the middle cleaning channel (3) and the lower cleaning channel (4) are all semi-cylindrical; the bottom of the outlet end of the lower cleaning channel (4) is open.

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