Vertical screw conveyor and 3D printing device

Abstract

The utility model discloses vertical spiral conveying device and 3D printing equipment relates to 3D printing technical field, the shell of up and down extension is equipped with the cavity with lower end opening and the feeding portion and the blanking portion that all intercommunication cavity, and the feeding portion is located the blanking portion below, the screw shaft in the cavity is coaxial with the shell and is set, and its upper end is rotatably connected in the shell, and the sealed discharge assembly is located lower end opening, and is connected the shell to close lower end opening, and the lower end of screw shaft is rotatably connected in the sealed discharge assembly through bearing assembly, and the upper surface of sealed discharge assembly is annular sealed connection with screw shaft, and forms interval space, and interval space is located annular sealed connection place near screw shaft one side, and the sealed discharge assembly is equipped with a plurality of discharge channels, and the upper end of discharge channel is the feeding end that communicates with interval space, and its lower end is the discharge end that can communicate with the cavity outside. Avoid the condition that powder leaks to the bearing on screw shaft in prior art through powder discharging mode, guarantee the smooth rotation of screw shaft.

Description

Technical Field

[0001] This utility model relates to the field of 3D printing technology, and in particular to a vertical spiral conveying device and a 3D printing equipment. Background Technology

[0002] In the operation of sand mold 3D printing equipment, a digital model is printed into a solid sand mold by layering sand (such as quartz sand, zircon sand, etc.) and selectively spraying binder (such as furan resin or inorganic binder). The structure of sand mold 3D printing equipment typically includes a powder spreading device, a mixing device, a binder spraying device (or inkjet device), and a sand recovery device. Among them, the mixing device can fully mix old sand and new sand, and the mixed sand is transported to the powder spreading device by a conveyor for layer-by-layer powder spreading.

[0003] Currently, screw conveyors are generally used to transfer sand from the mixing device to the powder spreading device. However, in actual powder spreading printing processes, the following problems have been found: due to poor or gradually decreasing sealing between the screw shaft and the housing in the screw conveyor, some sand inside the housing leaks and enters the bearing between the screw shaft and the housing, causing easy damage to the bearing and obstruction of the screw shaft's rotation. This severely affects the conveying operation of the screw conveyor and even the 3D printing process. Therefore, existing screw conveyors require further structural improvements. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a vertical screw conveyor and a 3D printing equipment, which avoids the situation in the prior art where powder leaks and enters the bearing on the screw shaft by means of powder discharge, thereby ensuring that the screw shaft can rotate smoothly.

[0005] The first aspect of this utility model provides a vertical spiral conveying device, which includes:

[0006] A housing extending vertically, the housing having a cavity and a feeding section and a discharging section both communicating with the cavity, the cavity having a lower opening, and the feeding section being located below the discharging section;

[0007] A screw shaft is disposed within the cavity, and its upper end is rotatably connected to the housing. The screw shaft and the housing are coaxially arranged.

[0008] Bearing assembly;

[0009] A sealing discharge assembly is provided at the lower opening and connected to the housing to close the lower opening. The sealing discharge assembly is rotatably connected to the lower end of the screw shaft through the bearing assembly. The upper surface of the sealing discharge assembly is annularly sealed to the screw shaft, forming a gap space. The gap space is located on the side of the annular sealing connection between the sealing discharge assembly and the screw shaft, close to the screw shaft. The sealing discharge assembly has several discharge channels. The upper end of the discharge channel is a feed end and communicates with the gap space. The lower end of the discharge channel is a discharge end that can communicate with the outside of the cavity.

[0010] The vertical screw conveying device according to the first aspect of this utility model has at least the following beneficial effects: when powder enters the cavity of the housing from the feeding section, the powder is conveyed upwards and exits from the discharging section by the rotation of the screw shaft, thereby realizing the vertical screw conveying function of the powder; the sealing discharge assembly is fixedly installed at the lower opening of the cavity to prevent powder leakage from the lower opening; the sealing discharge assembly and the lower end of the screw shaft are rotatably connected through a bearing assembly; to prevent powder from easily leaking and entering the bearing assembly, an annular sealing connection is made between the upper surface of the sealing discharge assembly and the screw shaft to improve sealing. However, the annular seal connection cannot completely prevent powder leakage. Some powder will still pass through the annular seal connection and enter the gap space, and further down into the bearing assembly, causing accelerated wear of the bearing assembly and reduced lubrication. Therefore, the sealing discharge assembly is equipped with several discharge channels. The inlet end of the discharge channel is connected to the gap space, which can discharge the powder that leaks into the gap space and prevent the powder in the gap space from entering the bearing assembly. This can protect the bearing assembly on the screw shaft and prevent the bearing assembly from being easily damaged and the screw shaft from rotating unevenly.

[0011] In some embodiments of this utility model, multiple discharge channels are provided and arranged in a circular pattern around the central axis of the screw shaft.

[0012] In some embodiments of this utility model, a plurality of labyrinth sealing structures are provided between the upper surface of the sealing discharge assembly and the screw shaft. The labyrinth sealing structures are located on the side of the annular sealing connection close to the screw shaft, and the interval space is located between the labyrinth sealing structure and the annular sealing connection or between any two adjacent labyrinth sealing structures.

[0013] In some embodiments of this utility model, the sealing discharge assembly includes a first end cap and a felt ring. The central axis of the felt ring extends in the vertical direction. The first end cap is detachably connected to the housing and is configured to block the lower opening. The upper surface of the first end cap and the screw shaft are connected in annular seal by the felt ring. The first end cap is provided with the discharge channel. The upper surface of the first end cap is provided with a plurality of coaxially arranged annular protrusions. The screw shaft is provided with a plurality of coaxially arranged annular grooves. The annular protrusions and the annular grooves are adapted to be connected to form the labyrinth seal structure. The bearing assembly is disposed between the screw shaft and the first end cap.

[0014] In some embodiments of this utility model, the sealing discharge assembly further includes a pressure cap, an umbrella-shaped sleeve, and a bearing seat. The bearing seat is located below the first end cover and partially connected to it. The bearing assembly is located on the bearing seat and sleeved on the screw shaft. The umbrella-shaped sleeve is sleeved on the screw shaft and located between the first end cover and the bearing assembly. A felt ring is provided between the umbrella-shaped sleeve and the bearing seat. A felt ring is provided between the outer circumferential surface of the screw shaft and the first end cover. A pressure cap is provided between the umbrella-shaped sleeve and the felt ring. The pressure cap is configured to simultaneously abut against the felt ring and the umbrella-shaped sleeve in the vertical direction.

[0015] In some embodiments of this utility model, the sealing discharge assembly further includes a skeleton oil seal, the central axis of which extends in the vertical direction, and the skeleton oil seal is provided between the bearing housing and the umbrella sleeve, the skeleton oil seal being located between the felt ring on the bearing assembly and the umbrella sleeve.

[0016] In some embodiments of this utility model, the bearing housing is provided with a plurality of discharge holes, which extend and pass through each other in the vertical direction and are arranged in a circle around the central axis of the screw shaft. The upper end of the discharge hole is connected to the discharge end.

[0017] In some embodiments of this utility model, the vertical screw conveyor further includes a second end cover and a third end cover. The second end cover is disposed below the screw shaft and connected to the bearing assembly, and the third end cover is disposed below the bearing seat and connected to the bearing seat.

[0018] In some embodiments of this utility model, the bearing assembly includes tapered roller bearings and deep groove ball bearings arranged sequentially in the vertical direction.

[0019] A second aspect of this invention provides a 3D printing device including a vertical spiral conveyor as described in any of the first aspects of the invention, the vertical spiral conveyor being configured to convey powder.

[0020] The 3D printing equipment according to the second aspect of the present invention has at least the following beneficial effects: the vertical spiral conveying device with the above-described structure is used in the 3D printing equipment to complete the powder conveying work. Moreover, during the powder conveying process, the powder leaking into the interval space can be effectively discharged through the discharge channel on the sealed discharge assembly, avoiding the situation where the powder enters the bearing assembly on the screw shaft downwards and affects the operation of the bearing assembly, thereby causing the bearing assembly to be easily damaged and the smoothness of the screw shaft rotation to be reduced.

[0021] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0022] Figure 1 This is a structural schematic diagram of the vertical screw conveyor provided according to an embodiment of the present utility model;

[0023] Figure 2 This is a schematic diagram showing the connection between the sealing discharge assembly and the housing and the screw shaft according to an embodiment of the present invention;

[0024] Figure 3 This is a structural schematic diagram of the sealing discharge assembly provided according to an embodiment of the present utility model.

[0025] Reference numerals: 100, Vertical screw conveyor; 110, Housing; 111, Feed port; 112, First flange; 113, Second flange; 114, Cavity; 120, Discharge pipe; 130, Screw shaft; 140, Sealing discharge assembly; 141, Felt ring; 142, First end cover; 143, Annular protrusion; 144, Discharge channel; 145, Pressure cap; 146, Umbrella sleeve; 147, Skeleton oil seal; 148, Bearing housing; 149, Discharge hole; 151, Tapered roller bearing; 152, Deep groove ball bearing; 153, Second end cover; 154, Third end cover. Detailed Implementation

[0026] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0027] In the description of this utility model, it should be understood that features specified as "first" or "second" may explicitly or implicitly include one or more of those features. In the description of this utility model, unless otherwise stated, "multiple" means two or more.

[0028] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0029] The following is for reference. Figures 1 to 3 This invention describes a vertical spiral conveying device and a 3D printing equipment provided according to embodiments of the present invention.

[0030] like Figures 1 to 3 As shown, the vertical screw conveyor 100 according to the first aspect embodiment of this utility model can be applied to 3D printing equipment and can realize the function of powder conveying. The vertical screw conveyor 100 of this embodiment avoids the situation of powder leakage and entering the bearing on the screw shaft 130 as in the prior art by the powder discharge method, thereby ensuring that the screw shaft 130 can rotate smoothly.

[0031] The vertical screw conveyor 100 has a vertical direction and a first direction, wherein the first direction is perpendicular to the vertical direction. In this embodiment, it is assumed that the first direction is the left-right direction.

[0032] like Figures 1 to 3 As shown, the vertical screw conveyor 100 includes a housing 110, a screw shaft 130, a bearing assembly, and a sealed discharge assembly 140.

[0033] The length of the shell 110 extends in the vertical direction. The shell 110 is hollow inside to form a cavity 114. The cavity 114 extends downward and has a lower opening. The shell 110 is provided with a feeding part and a discharging part. The feeding part is located below the discharging part. Both the feeding part and the discharging part are connected to the cavity 114.

[0034] In this embodiment, as Figure 1 and Figure 2As shown, the cavity 114 is cylindrical, with the feeding section and the discharging section located on opposite sides of the housing 110 along the first direction. A feeding port 111 is provided on the outer circumferential surface of the lower end of the housing 110. The feeding port 111 is open on one side along the first direction, and a first flange 112 is provided at the feeding port 111. The first flange 112 can be bolted to a feeding pipe. In this case, the feeding pipe or the feeding port 111 can be configured as the feeding section, allowing powder to enter the cavity 114. A discharging port is provided on the outer circumferential surface of the upper end of the housing 110, and a discharging pipe 120 is provided at the discharging port. The discharging pipe 120 is inclined downwards and has a downward-opening outlet. In this case, the discharging port or the discharging pipe 120 can be configured as the discharging section, allowing powder to flow out through the discharging section and leave the cavity 114.

[0035] The screw shaft 130 extends vertically and is housed within the cavity 114 of the housing 110. The upper end of the screw shaft 130 is rotatably connected to the housing 110. Specifically, the upper end of the screw shaft 130 is mounted on the housing 110 via a bearing, making the screw shaft 130 and the housing 110 coaxial. The outer circumferential surface of the upper end of the housing 110 has an opening structure with a second flange 113. A rotary actuator, including a drive motor and a transmission structure such as a reducer, can be bolted to the second flange 113. The output end of the rotary actuator is connected to the upper end of the screw shaft 130 through the opening structure to drive the screw shaft 130 to rotate around its central axis. During the rotation of the screw shaft 130, the helical blades on the screw shaft 130 can convey the powder in the cavity 114 upwards, allowing the powder to reach the discharge section and exit the cavity 114.

[0036] In this embodiment, as Figure 2 and Figure 3 As shown, the bearing assembly includes a tapered roller bearing 151 and a deep groove ball bearing 152, wherein the tapered roller bearing 151 and the deep groove ball bearing 152 are arranged sequentially in a vertical direction, with the tapered roller bearing 151 located above the deep groove ball bearing 152. This design can accommodate both axial and radial load capacities. The number of tapered roller bearings 151 and deep groove ball bearings 152 is not limited to one. Of course, in other embodiments, it is possible that the bearing assembly includes only a number of tapered roller bearings 151 or a number of deep groove ball bearings 152.

[0037] A sealing discharge assembly 140 is located at the lower opening of the cavity 114 and is fixedly connected to the housing 110, such as by bolts, so that the sealing discharge assembly 140 can close the lower opening of the cavity 114. The sealing discharge assembly 140 and the lower end of the screw shaft 130 are rotatably connected via a bearing assembly, allowing the screw shaft 130 to rotate within the cavity 114. The bearing assembly is sleeved on the lower end of the screw shaft 130 and mounted on the sealing discharge assembly 140.

[0038] Furthermore, the upper surface of the sealing discharge assembly 140 is connected to the screw shaft 130 in an annular seal, forming a gap space. This gap space is located on the side of the annular seal connection between the sealing discharge assembly 140 and the screw shaft 130, closer to the screw shaft 130; that is, the gap space is located inside the annular seal connection. Specifically, a plurality of labyrinth seal structures are provided between the upper surface of the sealing discharge assembly 140 and the screw shaft 130. These labyrinth seal structures are located on the side of the annular seal connection closer to the screw shaft 130, and the gap space is located between the labyrinth seal structures and the annular seal connection, or between any two adjacent labyrinth seal structures. Through the arrangement of the labyrinth seal structures, an annular seal connection can be achieved between the upper surface of the sealing discharge assembly 140 and the screw shaft 130.

[0039] In a specific embodiment, such as Figure 2 and Figure 3 As shown, the sealing discharge assembly 140 includes a first end cap 142 and a felt ring 141. The central axis of the felt ring 141 extends vertically, and when viewed vertically, the felt ring 141 is annular. The first end cap 142 can be detachably connected to the housing 110 by bolts, and the first end cap 142 is configured to seal the lower opening of the cavity 114.

[0040] The upper surface of the first end cap 142 is annularly sealed to the screw shaft 130 via a felt ring 141. Specifically, the upper surface of the first end cap 142 has a first annular groove, and the outer circumferential surface of the screw shaft 130 protrudes outward to form an annular plate, which is located above the first end cap 142. The lower surface of the annular plate has a second annular groove. The first groove and the second groove are vertically opposite to each other and are connected, thus allowing the felt ring 141 to be placed into the first groove and the second groove. There is a certain vertical distance between the upper surface of the first end cap 142 and the lower surface of the annular plate, thus forming a gap space between the first end cap 142 and the annular plate. The gap space is located on the inner circumference of the felt ring 141. The felt ring 141 provides a good seal, preventing powder from entering the gap space or even the bearing assembly.

[0041] Furthermore, the upper surface of the first end cap 142 is provided with several annular protrusions 143, which are coaxially arranged. The annular protrusions 143 are integrally formed with the first end cap 142 and are coaxially arranged with the screw shaft 130. The screw shaft 130 is provided with several annular grooves, which are coaxially arranged with the screw shaft 130. The annular grooves and the annular protrusions 143 are arranged vertically opposite each other. The annular protrusions 143 and the annular grooves are adapted to connect and form a labyrinth seal structure.

[0042] In this embodiment, there are two labyrinth sealing structures. An annular groove is provided on the lower surface of the annular plate. There are two annular grooves and two annular protrusions 143. The space between the two annular protrusions 143 is located between the two annular protrusions 143. For the area defined between one of the annular protrusions 143 and the felt ring 141, there is a gap between the first end cap 142 and the annular plate. For the area defined between the other annular protrusion 143 and the outer peripheral surface of the screw shaft 130, there is also a gap between the first end cap 142 and the annular plate.

[0043] The bearing assembly is located between the screw shaft 130 and the first end cover 142. The bearing assembly is situated below the felt ring 141 and can be mounted on the first end cover 142. Understandably, when the felt ring 141 experiences wear that reduces its sealing effectiveness, the labyrinth seal structure provides a good seal, further preventing powder from entering the bearing assembly.

[0044] The sealing discharge assembly 140 is provided with a plurality of discharge channels 144. The upper end of the discharge channel 144 is designated as the inlet end, and the inlet end is connected to the spacer. The lower end of the discharge channel 144 is designated as the discharge end, which can communicate with the outside of the cavity 114. In this embodiment, the first end cover 142 is provided with a plurality of discharge channels 144. The discharge channels 144 are inclined. Specifically, the upper end of the discharge channel 144 is closer to the screw shaft 130 than the lower end of the discharge channel 144, that is, the discharge channel 144 is inclined from top to bottom and outward. There are multiple discharge channels 144, and the multiple discharge channels 144 are arranged in a circle around the central axis of the screw shaft 130.

[0045] It is understandable that the specific shape, size, and quantity of the discharge channel 144 can be set according to actual needs and are not limited here. Even if the felt ring 141 is worn down, resulting in a reduced sealing effect, the labyrinth seal structure can still be used to prevent powder from entering the gap space or even the bearing assembly. In this case, a small amount of powder may bypass the labyrinth seal structure and enter the gap space. At this time, the powder in the gap space is discharged out through the discharge channel 144 to avoid the situation where too much powder accumulates in the gap space and can enter the bearing assembly, thereby causing the bearing assembly to be easily damaged.

[0046] In the use of the vertical screw conveyor 100 provided in the first aspect embodiment of this utility model, when the powder enters the cavity 114 of the housing 110 from the feeding part, the powder is conveyed upward and leaves from the unloading part by the rotation of the screw shaft 130, thereby realizing the vertical screw conveying function of the powder.

[0047] The sealing discharge assembly 140 is fixedly installed at the lower opening of the cavity 114 to prevent powder from leaking from the lower opening. The sealing discharge assembly 140 and the lower end of the screw shaft 130 are rotatably connected through a bearing assembly. To prevent powder from easily leaking and entering the bearing assembly, an annular sealing connection is made between the upper surface of the sealing discharge assembly 140 and the screw shaft 130 to improve the sealing effect.

[0048] However, the annular seal connection cannot completely prevent powder leakage. Some powder will still pass through the annular seal connection and enter the interval space, and further down into the bearing assembly, causing accelerated wear of the bearing assembly and reduced lubrication. Therefore, the sealing discharge assembly 140 is provided with several discharge channels 144. The inlet end of the discharge channel 144 is connected to the interval space, which can discharge the powder that leaks into the interval space, preventing the powder in the interval space from entering the bearing assembly. This can protect the bearing assembly on the screw shaft 130 and prevent the vertical screw conveyor 100 from failing to transport powder normally due to easily damaged bearing assemblies and uneven rotation of the screw shaft 130. Figure 3 As shown in the figure, the arrows indicate the direction of powder discharge.

[0049] In some embodiments, such as Figure 2 and Figure 3As shown, the sealing discharge assembly 140 also includes a pressure cap 145, an umbrella-shaped sleeve 146, and a bearing seat 148. The bearing seat 148 is located below the first end cap 142, with a vertical gap between it and the first end cap 142. The bearing seat 148 and the first end cap 142 are partially connected. Specifically, the bearing seat 148 has multiple first connecting parts, and the first end cap 142 has multiple second connecting parts. The multiple first connecting parts and multiple second connecting parts are arranged in a one-to-one correspondence, and they are all arranged circumferentially around the central axis of the screw shaft 130. The first connecting parts and the corresponding second connecting parts are fixedly connected by bolts.

[0050] The bearing assembly is mounted on the bearing housing 148 and sleeved on the screw shaft 130. Specifically, the inner ring of the bearing assembly is mounted on the screw shaft 130 via a sleeve, and the outer ring of the bearing assembly is fixedly connected to the bearing housing 148. An umbrella-shaped sleeve 146 is sleeved on the screw shaft 130 and is located between the first end cap 142 and the bearing assembly. A felt ring 141 is provided between the umbrella-shaped sleeve 146 and the bearing housing 148, and between the outer circumferential surface of the screw shaft 130 and the first end cap 142. A pressure cap 145 is provided between the umbrella-shaped sleeve 146 and the felt ring 141. The pressure cap 145 is configured to simultaneously abut against the felt ring 141 and the umbrella-shaped sleeve 146 in the vertical direction. The limiting effect of the umbrella-shaped sleeve 146 keeps the pressure cap 145 stationary, and under the pressure of the pressure cap 145, the felt ring 141 remains stably stationary.

[0051] Understandably, the felt ring 141 between the upper surface of the first end cover 142 and the screw shaft 130 is defined as the first felt ring. Since the screw shaft 130 needs to pass through the first end cover 142 and connect with the bearing assembly on the bearing housing 148, the second end cover 153 is provided with a central through hole so that the lower end of the screw shaft 130 can pass through. At this time, the felt ring 141 between the inner circumferential surface of the central through hole of the second end cover 153 and the outer circumferential surface of the screw shaft 130 is defined as the second felt ring, and the felt ring 141 between the umbrella sleeve 146 and the bearing housing 148 is defined as the third felt ring. The first felt ring, the second felt ring and the third felt ring are arranged alternately from top to bottom.

[0052] The pressure cap 145 corresponding to the second felt ring is defined as the first pressure cap, and the pressure cap 145 corresponding to the third felt ring is defined as the second pressure cap. The first pressure cap is located above the umbrella-shaped sleeve 146 and the second pressure cap, and below the second felt ring. The upper surface of the first pressure cap can abut against the second felt ring, and the first pressure cap can be supported and limited by the umbrella-shaped sleeve 146. The second pressure cap is located above the third felt ring, the lower surface of the second pressure cap can abut against the third felt ring, and the second pressure cap can be pressed down and limited by the umbrella-shaped sleeve 146. The cross-sectional shape of the first pressure cap and the cross-sectional shape of the second pressure cap are not limited. The lower end of the screw shaft 130 is cylindrically stepped.

[0053] In some embodiments, such as Figure 2 and Figure 3 As shown, the sealing discharge assembly 140 also includes a skeleton oil seal 147. The central axis of the skeleton oil seal 147 extends vertically, and the skeleton oil seal 147 is positioned between the bearing housing 148 and the umbrella-shaped sleeve 146. Furthermore, the skeleton oil seal 147 is located between the bearing assembly and the felt ring 141 on the umbrella-shaped sleeve 146. Specifically, the skeleton oil seal 147 is fitted onto the umbrella-shaped sleeve 146, with its inner circumferential surface abutting against the umbrella-shaped sleeve 146 and its outer circumferential surface abutting against the bearing housing 148. The skeleton oil seal 147 isolates the bearing assembly from the felt ring 141, preventing lubricating oil from leaking into the cavity 114 and contaminating the powder. Simultaneously, it ensures that the bearing assembly remains in a lubricated state for a long period, reducing wear.

[0054] In some embodiments, such as Figure 2 and Figure 3 As shown, the bearing housing 148 is provided with multiple discharge holes 149, which extend and connect vertically. These discharge holes 149 are arranged circumferentially around the central axis of the screw shaft 130, with their upper ends connected to the discharge end. In this embodiment, the inner diameter of the discharge holes 149 is larger than the inner diameter of the discharge channel 144. The discharge holes 149 and discharge channels 144 are arranged in a one-to-one correspondence. It is understood that when powder is discharged through the discharge channel 144, it will fall onto the bearing housing 148 and be located in the outer area of ​​the umbrella-shaped sleeve 146, allowing for powder removal by personnel. By providing the discharge holes 149, the powder on the bearing housing 148 can be guided and discharged downwards, preventing excessive powder accumulation on the bearing housing 148 and reducing the frequency of cleaning.

[0055] In some embodiments, such as Figure 2 and Figure 3As shown, the vertical screw conveyor 100 also includes a second end cover 153 and a third end cover 154. The second end cover 153 is located below the screw shaft 130, and it can be fixedly connected to the bearing assembly via bolts or a capping method. The third end cover 154 is located below the bearing housing 148, and it can also be fixedly connected to the bearing housing 148 via bolts or a capping method. It is understood that by providing the second end cover 153 and the third end cover 154, the bearing assembly can be protected, preventing external dust and other contaminants from affecting it.

[0056] like Figures 1 to 3 As shown, the 3D printing equipment according to the second aspect embodiment of the present invention includes a vertical spiral conveyor 100 as in the first aspect embodiment, wherein the vertical spiral conveyor 100 is configured to convey powder.

[0057] Understandably, the vertical screw conveyor 100 can be used between the used sand recycling device and the mixing device in a 3D printing equipment to transport the recycled used sand to the mixing device, allowing the used sand to mix with the new sand and improving the utilization rate of the used sand. Furthermore, the vertical screw conveyor 100 can also be used between the mixing device and the powder spreading device in a 3D printing equipment to transport the mixed sand (or powder) to the powder spreading device, enabling the powder spreading device to perform layer-by-layer powder spreading on the printing plane.

[0058] In the 3D printing equipment provided in the second aspect embodiment of this utility model, by applying the vertical spiral conveying device 100 with the above-described structure, the powder conveying work can be completed. Moreover, during the powder conveying process, the powder leaking into the interval space can be effectively discharged through the discharge channel 144 on the sealed discharge assembly 140, avoiding the situation where the powder enters the bearing assembly on the screw shaft 130 downwards and affects the operation of the bearing assembly, thereby causing the bearing assembly to be easily damaged and the smoothness of the screw shaft 130 to be reduced. Ultimately, it can ensure that the 3D printing equipment can work normally for a long time and complete the 3D printing task.

[0059] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A vertical screw conveyor, characterized in that, include: A housing extending vertically, the housing having a cavity and a feeding section and a discharging section both communicating with the cavity, the cavity having a lower opening, and the feeding section being located below the discharging section; A screw shaft is disposed within the cavity, and its upper end is rotatably connected to the housing. The screw shaft and the housing are coaxially arranged. Bearing assembly; A sealing discharge assembly is provided at the lower opening and connected to the housing to close the lower opening. The sealing discharge assembly is rotatably connected to the lower end of the screw shaft through the bearing assembly. The upper surface of the sealing discharge assembly is annularly sealed to the screw shaft, forming a gap space. The gap space is located on the side of the annular sealing connection between the sealing discharge assembly and the screw shaft, close to the screw shaft. The sealing discharge assembly has several discharge channels. The upper end of the discharge channel is a feed end and communicates with the gap space. The lower end of the discharge channel is a discharge end that can communicate with the outside of the cavity.

2. The vertical screw conveyor according to claim 1, characterized in that, The discharge channels are provided in multiple ways and are arranged in a circle around the central axis of the screw shaft.

3. The vertical screw conveyor according to claim 2, characterized in that, The upper surface of the sealing discharge assembly is provided with a plurality of labyrinth sealing structures between it and the screw shaft. The labyrinth sealing structures are located on the side of the annular sealing connection close to the screw shaft. The gap space is located between the labyrinth sealing structure and the annular sealing connection or between any two adjacent labyrinth sealing structures.

4. The vertical screw conveyor according to claim 3, characterized in that, The sealing and discharging assembly includes a first end cap and a felt ring. The central axis of the felt ring extends vertically. The first end cap is detachably connected to the housing and configured to block the lower opening. The upper surface of the first end cap and the screw shaft are connected in annular seal by the felt ring. The first end cap has the discharge channel. The upper surface of the first end cap has several coaxially arranged annular protrusions. The screw shaft has several coaxially arranged annular grooves. The annular protrusions and annular grooves are adapted to each other and form the labyrinth seal structure. The bearing assembly is located between the screw shaft and the first end cap.

5. The vertical screw conveyor according to claim 4, characterized in that, The sealing discharge assembly further includes a pressure cap, an umbrella-shaped sleeve, and a bearing seat. The bearing seat is located below the first end cover and is partially connected to the first end cover. The bearing assembly is located on the bearing seat and sleeved on the screw shaft. The umbrella-shaped sleeve is sleeved on the screw shaft and located between the first end cover and the bearing assembly. The felt ring is provided between the umbrella-shaped sleeve and the bearing seat. The felt ring is provided between the outer circumferential surface of the screw shaft and the first end cover. The pressure cap is provided between the umbrella-shaped sleeve and the felt ring. The pressure cap is configured to simultaneously abut against the felt ring and the umbrella-shaped sleeve in the vertical direction.

6. The vertical screw conveyor according to claim 5, characterized in that, The sealing and discharging assembly also includes a skeleton oil seal, the central axis of which extends in the vertical direction. The skeleton oil seal is provided between the bearing housing and the umbrella sleeve, and is located between the felt ring on the bearing assembly and the umbrella sleeve.

7. The vertical screw conveyor according to claim 5, characterized in that, The bearing housing is provided with multiple discharge holes, which extend and connect in the vertical direction and are arranged in a circle around the central axis of the screw shaft. The upper end of each discharge hole is connected to the discharge end.

8. The vertical screw conveyor according to claim 5, characterized in that, It also includes a second end cap and a third end cap. The second end cap is located below the screw shaft and is connected to the bearing assembly. The third end cap is located below the bearing housing and is connected to the bearing housing.

9. The vertical screw conveyor according to any one of claims 1 to 8, characterized in that, The bearing assembly includes tapered roller bearings and deep groove ball bearings arranged sequentially in the vertical direction.

10. A 3D printing device, characterized in that, Includes the vertical screw conveyor as described in any one of claims 1 to 9, wherein the vertical screw conveyor is configured to convey powder.

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