Material filling equipment

Abstract

The utility model discloses material filling equipment. The material filling equipment comprises a material filling plate and a jig plate which are arranged in a stacked mode. A filling hole channel is formed in the filling plate; the jig plate is provided with a containing hole channel and a material guiding hole channel which communicate with each other, and the material guiding hole channel is close to the material filling plate and used for communicating with the material filling hole channel. Wherein the material guiding hole channel comprises a first discharging port arranged close to the containing hole channel, the size of a hole opening of the first discharging port is smaller than the diameter of the containing hole channel so that a step-shaped limiting face can be formed at the transition position of the containing hole channel and the material guiding hole channel, the paper tube can be contained in the containing hole channel, and the size of the hole opening of the first discharging port is not larger than the inner diameter of the paper tube. Due to the fact that the hole size of the first discharging hole of the material guiding hole channel is not larger than the inner diameter of the paper tube, the granular materials of the material guiding hole channel can be completely filled into the paper tube, the filling amount of each paper tube can be the same, the consistency of products is improved, and the cleaning difficulty of material filling equipment can be lowered.

Description

Technical Field

[0001] This application relates to the field of manufacturing technology of heated non-combustible products, specifically to a filling device. Background Technology

[0002] The granular material of heated non-combustible products refers to granules of a certain size made by mixing smoke-generating materials, atomizing agents, and flavoring substances. These granules are typically filled into paper tubes using filling equipment to form heated non-combustible products. The filling equipment usually includes a filling plate with multiple filling channels. By placing the paper tube at the outlet of the filling channels, batch filling of granular materials can be achieved.

[0003] However, during the filling process, granular materials are prone to scattering outside the paper tube, which not only affects the consistency of the product, but also increases the difficulty of cleaning the filling equipment. Utility Model Content

[0004] This application provides a filling device to solve the problem that granular materials are easily scattered outside the paper tube during the filling process of existing filling devices, thereby affecting product consistency and increasing the difficulty of cleaning the filling device.

[0005] In one embodiment, a filling device is provided for filling granular materials into paper tubes of heat-resistant non-combustible articles. The filling device includes: a filling plate and a fixture plate stacked together.

[0006] The filling plate is provided with filling channels;

[0007] The fixture plate is provided with an accommodating channel and a guiding channel that are interconnected. The guiding channel is located close to the filling plate and is used to communicate with the filling channel.

[0008] The material guiding channel includes a first discharge port located near the receiving channel. The opening size of the first discharge port is smaller than the diameter of the receiving channel, so as to form a stepped limiting surface at the transition between the receiving channel and the material guiding channel. The paper tube can be accommodated in the receiving channel, and the opening size of the first discharge port is not greater than the inner diameter of the paper tube.

[0009] In one embodiment, the jig plate includes: a first plate and a second plate stacked together, the first plate being close to the filling plate;

[0010] The receiving channel includes a first receiving section and a second receiving section, wherein the first receiving section and the material guiding channel are formed in the first plate, and the second receiving section is formed in the second plate.

[0011] In one embodiment, the orifice size of the first receiving section and the second receiving section are the same.

[0012] In one embodiment, the filling device further includes: a baffle plate, the baffle plate being disposed between the filling plate and the fixture plate and being movable relative to the filling plate between a first position and a second position;

[0013] The baffle plate is provided with a connecting channel. When the baffle plate is in the first position, the connecting channel corresponds to the position of the filling channel, so that the granular material enters the guiding channel from the filling channel. When the baffle plate is in the second position, the connecting channel is offset from the position of the filling channel, so as to prevent the granular material from entering the guiding channel from the filling channel.

[0014] In one embodiment, multiple connecting channels, filling channels, and guiding channels are provided. When the baffle plate is in the first position, one connecting channel corresponds to one filling channel and one guiding channel.

[0015] In one embodiment, the material guiding channel further includes a first inlet disposed away from the receiving channel, and the orifice size of the material guiding channel decreases along the direction from the first inlet to the first outlet.

[0016] In one embodiment, the jig plate includes a first top wall disposed near the filling plate, and the material guiding channel includes a first hole wall, wherein the angle α between the first hole wall and the first top wall is in the range of 95° to 130°.

[0017] In one embodiment, the filling channel includes a second outlet located near the guiding channel, the size of the second outlet being smaller than the size of the first inlet.

[0018] In one embodiment, the filling channel further includes a second inlet disposed away from the guiding channel, and the orifice size of the filling channel decreases along the direction from the second inlet to the second outlet.

[0019] In one embodiment, the filling plate includes a second top wall disposed away from the fixture plate, the filling channel includes a second hole wall, and the included angle β between the second hole wall and the second top wall is in the range of 95° to 130°.

[0020] According to the filling device of the above embodiment, since the orifice size of the first discharge port is smaller than the diameter of the receiving channel, a stepped limiting surface can be formed at the transition between the receiving channel and the guiding channel, thereby reliably confining the paper tube within the receiving channel for subsequent filling. Furthermore, since the fixture plate includes interconnected receiving channels and guiding channels, and the guiding channel is connected to the filling channel, during the filling process, the granular material entering the filling channel can smoothly enter the paper tube located in the receiving channel through the guiding channel, thus achieving filling. More importantly, since the orifice size of the first discharge port of the guiding channel is not larger than the opening size of the paper tube, all the granular material in the guiding channel can be filled into the paper tube. This not only ensures that the filling volume of each paper tube is the same, thereby improving product consistency, but also reduces the cleaning difficulty of the filling device. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the filling device in one embodiment;

[0022] Figure 2 This is a schematic diagram of the filling device when the baffle is in the first position in one embodiment;

[0023] Figure 3 This is a cross-sectional view of the filling device when the baffle is in the first position in one embodiment;

[0024] Figure 4 This is a schematic diagram of the filling device when the baffle is in the second position in one embodiment;

[0025] Figure 5 This is a cross-sectional view of the filling device when the baffle is in the second position in one embodiment.

[0026] The accompanying diagrams are labeled as follows:

[0027] 1- Filling plate, 11- Filling channel, 111- Second inlet, 112- Second outlet;

[0028] 2- Fixture plate, 21- First plate body, 22- Second plate body, 23- Guide channel, 231- First feed inlet, 232- First discharge outlet, 24- Accommodation channel, 241- First accommodation section, 242- Second accommodation section;

[0029] 3-Baffle plate, 31-Connecting channel;

[0030] 4-Limiting device;

[0031] 5-Paper tube;

[0032] 6-Workbench. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0034] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0035] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0036] The existing filling equipment has the problem that particulate matter easily scatters outside the paper tube during the filling process.

[0037] In this application, by setting a jig plate, and the orifice size of the jig plate's discharge port is smaller than the tube opening size of the paper tube, granular materials are effectively prevented from scattering outside the paper tube.

[0038] Please refer to Figures 1 to 5In one embodiment, a filling device is provided for filling granular material into a paper tube 5 of a heat-resistant non-combustible product. The filling device includes: a filling plate 1 and a fixture plate 2 stacked together; the filling plate 1 is provided with a filling channel 11; the fixture plate 2 is provided with a receiving channel 24 and a guiding channel 23 that are interconnected. The guiding channel 23 is located near the filling plate 1 and is used to communicate with the filling channel 11. The guiding channel 23 includes a first outlet 232 located near the receiving channel 24. The orifice size of the first outlet 232 is smaller than the diameter of the receiving channel 24, so as to form a stepped limiting surface at the transition between the receiving channel 24 and the guiding channel 23. The paper tube 5 can be accommodated in the receiving channel 24, and the orifice size of the first outlet 232 is not greater than the inner diameter of the paper tube 5. The phrase "the orifice size of the first discharge port 232 is not greater than the inner diameter of the paper tube 5" includes two cases: the orifice size of the first discharge port 232 is equal to the inner diameter of the paper tube 5, and the orifice size of the first discharge port 232 is less than the inner diameter of the paper tube 5.

[0039] In this embodiment, since the orifice size of the first discharge port 232 is smaller than the diameter of the receiving channel 24, a stepped limiting surface can be formed at the transition between the receiving channel 24 and the guiding channel 23, thereby reliably confining the paper tube 5 within the receiving channel 24 for subsequent filling. Furthermore, since the fixture plate 2 includes the interconnected receiving channel 24 and guiding channel 23, and the guiding channel 23 is connected to the filling channel 11, during the filling process, the granular material entering the filling channel 11 can smoothly enter the paper tube 5 located in the receiving channel 24 via the guiding channel 23, thus achieving filling. More importantly, since the orifice size of the first discharge port 232 of the guiding channel 23 is not larger than the opening size of the paper tube 5, all the granular material in the guiding channel 23 can be filled into the paper tube 5. This not only ensures that the filling amount of each paper tube 5 is the same, thereby improving product consistency, but also reduces the cleaning difficulty of the filling equipment.

[0040] It should be noted that, in order to better support and accommodate the paper tube 5, the opening size of the accommodating channel 24 should be slightly larger than the outer diameter of the paper tube 5. In one embodiment, the opening size of the accommodating channel 24 can be 0mm to 10mm, preferably 3mm to 6mm. It is understood that the opening size of the accommodating channel 24 is not limited to the above-mentioned size range, and those skilled in the art can adjust it according to the actual size of the paper tube 5.

[0041] Furthermore, this application embodiment does not limit the shape and number of the orifices of the filling channel 11, the receiving channel 24, and the guiding channel 23. The orifice shape includes, but is not limited to, circular, elliptical, triangular, rectangular, polygonal, or other shapes, which can be adjusted by those skilled in the art according to actual needs. In one embodiment, the orifices of the filling channel 11, the receiving channel 24, and the guiding channel 23 are all circular, and multiple of each are provided. These multiple filling channels 11, receiving channels 24, and guiding channels 23 are arranged in an array, and each of the filling channels 11, receiving channels 24, and guiding channels 23 corresponds one-to-one and is coaxially arranged, ensuring product consistency while achieving mass production.

[0042] In one embodiment, such as Figure 2 and Figure 4 As shown, the jig plate 2 includes: a first plate 21 and a second plate 22 stacked together, with the first plate 21 close to the filling plate 1; the receiving channel 24 includes a first receiving section 241 and a second receiving section 242, with the first receiving section 241 and the guiding channel 23 formed in the first plate 21, and the second receiving section 242 formed in the second plate 22. Furthermore, the first plate 21 and the second plate 22 can be connected by bolts, snap-fitting, or other means to achieve their alignment.

[0043] In this embodiment, since the jig plate 2 includes a first plate 21 and a second plate 22, the jig plate 2 is essentially disassembled. This reduces the processing difficulty of the jig plate 2 and allows it to accommodate paper tubes 5 of different sizes (including outer diameter and height) simply by replacing either the first plate 21 or the second plate 22, thus improving the versatility of the jig plate 2. Furthermore, before filling, the second plate 22 can be fixed on the worktable 6, and then the paper tube 5 can be placed into the second receiving section 242 (at least a portion of the paper tube 5 protrudes from the first receiving section 241). Next, the first plate 21 is aligned and installed above the second plate 22, so that the portion of the paper tube 5 protruding from the first receiving section 241 is embedded within the first receiving section 241, allowing the paper tube 5 to be conveniently and accurately installed in the jig plate 2. In summary, by disassembling the jig plate 2 into a first plate 21 and a second plate 22, the difficulty of assembling the paper tube 5 into the jig plate 2 can be reduced.

[0044] Since the paper tube 5 is generally cylindrical, when the orifice sizes of the first accommodating section 241 and the second accommodating section 242 are the same, not only can the processing difficulty of the jig plate 2 be reduced, but the paper tube 5 can also be better supported. Furthermore, this embodiment does not limit the height of the first accommodating section 241 and the second accommodating section 242; those skilled in the art can adjust them according to the actual height of the paper tube 5. In one embodiment, the sum of the heights of the first accommodating section 241 and the second accommodating section 242 can be consistent with the height of the paper tube 5, thereby eliminating gaps between the orifice of the paper tube 5 and the first discharge port 232 of the guide channel 23, further reducing the possibility of particulate material scattering outside the paper tube 5.

[0045] In one embodiment, such as Figures 2 to 5 As shown, the filling device also includes: a baffle plate 3, which is disposed between the filling plate 1 and the fixture plate 2 and can move relative to the filling plate 1 between a first position and a second position; the baffle plate 3 is provided with a connecting channel 31. When the baffle plate 3 is in the first position, the connecting channel 31 corresponds to the position of the filling channel 11 so that the granular material enters the guiding channel 23 from the filling channel 11. When the baffle plate 3 is in the second position, the connecting channel 31 is offset from the position of the filling channel 11 so as to prevent the granular material from entering the guiding channel 23 from the filling channel 11.

[0046] In this embodiment, a baffle plate 3 is provided, and the baffle plate 3 can move between a first position (i.e., the position corresponding to the connecting channel 31 and the filling channel 11) and a second position (i.e., the position where the connecting channel 31 and the filling channel 11 are offset). Thus, during the filling process, firstly, an external force is applied to the baffle plate 3 (e.g., pulling the baffle plate 3 along a 45° direction) to move the baffle plate 3 to the second position. At this point, the connecting channel 31 and the filling channel 11 are offset. When filling the filling channel 11, the baffle plate 3 can prevent granular material from falling into the guide channel of the fixture plate 2, ensuring that the filling amount of each paper tube 5 is only the granular material entering the filling channel. This achieves precise control of the filling amount of granular material, which is beneficial for improving product consistency. Then, an external force is applied to the baffle plate 3 (e.g., pulling the baffle plate 3 at a 45° angle) to move the baffle plate 3 to the first position. At this time, the connecting channel 31 corresponds to the filling channel 11, and the granular material in the filling channel falls smoothly into the guide channel 23 of the fixture plate 2, and is further filled into the paper tube 5. It can be understood that the first position and the second position are achieved by pulling the baffle plate 3 in opposite directions.

[0047] It should be noted that the embodiments of this application do not limit the shape and number of the orifices of the connecting channels 31. The orifice shape includes, but is not limited to, circles, ellipses, triangles, rectangles, polygons, or other shapes, and those skilled in the art can adjust them according to actual needs. In one embodiment, the orifice shape of the connecting channels 31 is circular, and multiple connecting channels 31 are arranged in an array. When the baffle plate 3 is in the first position, one connecting channel 31 corresponds to one filling channel 11 and is coaxially arranged, ensuring product consistency while achieving mass production. In addition, the baffle plate 3 can be pressed (not completely pressed, so as to allow the movement of the baffle plate 3) between the filling plate 1 and the fixture plate 2 by the mutual connection of the filling plate 1 and the fixture plate 2. The filling plate 1 and the fixture plate 2 can be connected by bolts, snap-fit, or other means to achieve the alignment connection between them.

[0048] In one embodiment, multiple connecting channels 31, filling channels 11, and guiding channels 23 are provided. When the baffle plate 3 is in the first position, one connecting channel 31 corresponds to one filling channel 11 and one guiding channel 23. This enables batch filling of granular materials, which is beneficial to improving the production efficiency of heat-resistant non-combustible products.

[0049] It should be noted that the embodiments of this application do not limit the arrangement of the multiple connecting channels 31, multiple filling channels 11, and multiple guiding channels 23, and those skilled in the art can make adjustments according to actual needs. In one embodiment, the multiple connecting channels 31, multiple guiding channels 23, and multiple filling channels 11 are all arranged in an array, and when the baffle plate 3 is in the first position, the filling channels 11, the receiving channels 24, and the guiding channels 23 correspond one-to-one and are coaxially arranged, ensuring product consistency while achieving mass production.

[0050] In one embodiment, such as Figure 2 As shown, the orifice size of the connecting channel 31 is between the orifice size of the first feed inlet 231 and the orifice size of the second discharge outlet 112. This allows all granular material entering the filling channel 11 to pass through the connecting channel 31 into the guiding channel 23, preventing the accumulation of granular material at the junction of the filling channel 11 and the connecting channel 31. This not only improves product consistency but also further avoids material waste and reduces the difficulty of cleaning the filling equipment.

[0051] It should be noted that the orifice size of the connecting channel 31 is between the orifice size of the first feed inlet 231 and the orifice size of the second discharge outlet 112. This means that the orifice size of the connecting channel 31 is greater than or equal to the orifice size of the first feed inlet 231 and less than or equal to the orifice size of the second discharge outlet 112. In one embodiment, considering machining tolerances, the orifice size of the connecting channel 31 is greater than the orifice size of the first feed inlet 231 and less than the orifice size of the second discharge outlet 112. This effectively avoids the accumulation of particulate material at the junction of the filling channel 11 and the connecting channel 31, and at the junction of the connecting channel 31 and the guiding channel 23.

[0052] In one embodiment, the material guiding channel 23 further includes a first inlet 231 disposed away from the receiving channel 24, and the orifice size of the material guiding channel 23 decreases along the direction from the first inlet 231 to the first outlet 232. In this way, it can play a good guiding role for granular materials, so that the granular materials entering the material guiding channel 23 can be smoothly poured into the paper tube 5.

[0053] In one embodiment, the jig plate 2 includes a first top wall located near the filling plate 1, and the guide channel 23 includes a first hole wall. The angle α between the first hole wall and the first top wall ranges from 95° to 130°. By further limiting the angle between the first hole wall and the first top wall, on the one hand, the flow path of the granular material can be optimized, allowing the granular material to be poured into the paper tube 5 more smoothly; on the other hand, it can avoid the phenomenon of a small amount of granular material accumulating on the first hole wall, so that all the granular material entering the guide channel 23 is poured into the paper tube 5, thereby achieving the goal of consistent filling volume in multiple paper tubes 5 filled simultaneously, which is beneficial to improving product consistency.

[0054] It should be noted that the specific value of the angle α between the first hole wall and the first top wall is not limited in the embodiments of this application. Those skilled in the art can adjust it according to the properties of the granular material itself. For example, the angle α between the first hole wall and the first top wall can be 95°, 105°, 110°, 125°, 130° or other values. Tests have shown that when each filling channel 11 is filled with granular material (i.e., the volume of granular material in each filling channel 11 is equal) and the bulk density of the granular material is equal, when the angle α between the first hole wall and the first top wall is 105°, the total weight deviation of the granular material in the entire filling plate 1 can be controlled to not exceed 10%, thereby significantly improving product consistency.

[0055] Furthermore, if the stacking direction of the filling plate 1 and the fixture plate 2 is the first direction, this embodiment does not limit the thickness of the filling plate 1 (i.e., the dimension of the filling plate 1 in the first direction) and the orifice size of the filling channel 11. Those skilled in the art can adjust them according to the actual required filling volume. In one embodiment, the thickness of the filling plate 1 can be 3mm to 40mm. More preferably, it is 6mm to 20mm.

[0056] In one embodiment, such as Figure 2 and Figure 4 As shown, the filling channel 11 includes a second outlet 112 located near the guiding channel 23. The opening size of the second outlet 112 is smaller than that of the first inlet 231. This ensures that all granular material entering the filling channel 11 enters the guiding channel 23, preventing the accumulation of granular material at the junction of the filling channel 11 and the guiding channel 23.

[0057] In one embodiment, the filling channel 11 further includes a second inlet 111 disposed opposite to the guiding channel 23, and the orifice size of the filling channel 11 decreases along the direction from the second inlet 111 to the second outlet 112. In this way, it can play a good guiding role for granular materials, so that the granular materials entering the filling channel 11 can fall smoothly into the guiding channel 23.

[0058] In one embodiment, the filling plate 1 includes a second top wall disposed away from the fixture plate 2, and the filling channel 11 includes a second hole wall. The angle β between the second hole wall and the second top wall ranges from 95° to 130°. By further limiting the angle between the second hole wall and the second top wall, on the one hand, the flow path of the granular material can be optimized, allowing the granular material to fall more smoothly into the guide channel 23; on the other hand, it can avoid the phenomenon of a small amount of granular material accumulating on the second hole wall, so that all the granular material entering the filling channel 11 falls into the guide channel 23, thereby making the filling amount of the multiple paper tubes 5 being filled simultaneously as consistent as possible.

[0059] It should be noted that the specific value of the angle β between the second hole wall and the second top wall is not limited in the embodiments of this application, and those skilled in the art can adjust it according to the properties of the granular material itself. For example, the angle β between the second hole wall and the second top wall can be 95°, 105°, 110°, 125°, 130° or other values.

[0060] In one embodiment, such as Figure 1As shown, the workbench 6 is also equipped with a limiting device 4. When the filling equipment is placed on the workbench 6, the limiting device 4 restricts the perimeter of the filling equipment. Specifically, the second plate 22 is cuboid and includes four side walls. The limiting device 4 includes three limiting plates, which abut against three of the four side walls respectively, to reliably limit the second plate 22 and even the entire filling equipment. Furthermore, handles can be provided on the side walls of the second plate 22 that do not abut against the limiting plates to facilitate the movement of the filling equipment.

[0061] The above-described specific examples are for illustrative purposes only and are not intended to limit the scope of this invention. Those skilled in the art to which this invention pertains can make various simple deductions, modifications, or substitutions based on the concept of this invention.

Claims

1. A filling device for filling granular materials into paper tubes of heat-resistant, non-combustible products, characterized in that, The filling equipment includes: a stacked filling plate and a fixture plate; The filling plate is provided with filling channels; The fixture plate is provided with an accommodating channel and a guiding channel that are interconnected. The guiding channel is located close to the filling plate and is used to communicate with the filling channel. The material guiding channel includes a first discharge port located near the receiving channel. The opening size of the first discharge port is smaller than the diameter of the receiving channel, so as to form a stepped limiting surface at the transition between the receiving channel and the material guiding channel. The paper tube can be accommodated in the receiving channel, and the opening size of the first discharge port is not greater than the inner diameter of the paper tube.

2. The filling equipment according to claim 1, characterized in that, The fixture plate includes: a first plate and a second plate stacked together, with the first plate close to the filling plate; The receiving channel includes a first receiving section and a second receiving section, wherein the first receiving section and the material guiding channel are formed in the first plate, and the second receiving section is formed in the second plate.

3. The filling equipment according to claim 2, characterized in that, The orifice size of the first receiving section and the second receiving section are the same.

4. The filling equipment according to claim 1, characterized in that, The filling device further includes: a baffle plate, which is disposed between the filling plate and the fixture plate and is movable relative to the filling plate between a first position and a second position; The baffle plate is provided with a connecting channel. When the baffle plate is in the first position, the connecting channel corresponds to the position of the filling channel, so that the granular material enters the guiding channel from the filling channel. When the baffle plate is in the second position, the connecting channel is offset from the position of the filling channel, so as to prevent the granular material from entering the guiding channel from the filling channel.

5. The filling equipment according to claim 4, characterized in that, Multiple connecting channels, filling channels, and guiding channels are provided. When the baffle plate is in the first position, one connecting channel corresponds to one filling channel and one guiding channel.

6. The filling equipment according to any one of claims 1-5, characterized in that, The material guiding channel also includes a first inlet located away from the receiving channel, and the orifice size of the material guiding channel decreases along the direction from the first inlet to the first outlet.

7. The filling equipment according to claim 6, characterized in that, The fixture plate includes a first top wall located near the filling plate, and the material guiding channel includes a first hole wall. The angle α between the first hole wall and the first top wall ranges from 95° to 130°.

8. The filling equipment according to claim 6, characterized in that, The filling channel includes a second outlet located near the guiding channel, and the size of the second outlet is smaller than that of the first inlet.

9. The filling equipment according to claim 8, characterized in that, The filling channel also includes a second inlet located away from the material guiding channel, and the orifice size of the filling channel decreases along the direction from the second inlet to the second outlet.

10. The filling equipment according to claim 8, characterized in that, The filling plate includes a second top wall disposed away from the fixture plate, and the filling channel includes a second hole wall. The angle β between the second hole wall and the second top wall ranges from 95° to 130°.

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