Sand remover for paper pulp production

Abstract

The utility model relates to the technical field of accessory devices of desanding devices, in particular to a desander for paper pulp production, which can smoothly discharge slag pulp, cannot block a pipeline, and can quickly filter paper pulp through two groups of filtering rotary drums with different rotating speeds. The desander for paper pulp production comprises a desander shell, a bottom plate, four sets of supporting legs, a sleeve, a first gear ring, a first rotating cylinder and a second rotating cylinder, the bottom end of the desander shell is connected with the bottom plate, the bottom end of the bottom plate is connected with the four sets of supporting legs, and the bottom plate is connected with the four sets of supporting legs. Discharging pipes are arranged at the left end and the right end of the sand remover shell respectively, a slag discharging pipe is arranged at the bottom end of the sand remover shell, and the slag discharging pipe penetrates out of the bottom end of the bottom plate in a sealed mode.

Description

Technical Field

[0001] The utility model relates to the technical field of auxiliary devices of sand removal devices, in particular to a sand remover for pulp production. Background Art

[0002] As is well known, the sand removal device is an important component device for pulp purification in the paper industry. Its main function is to purify the pulp, reduce paper dust, and improve the quality of paper products. When the existing sand removal device works, the pulp enters the sand removal device through the feed inlet, rotates and flows in the sand removal device, settles at the bottom of the sand removal device under the action of centrifugal force and its own gravity, realizes the separation of good pulp and waste residue, the good pulp is discharged from the discharge port, and the pulp containing waste residue is discharged through the slag discharge pipe;

[0003] However, it is very difficult for the high-concentration slag slurry to be discharged from the slag discharge port, often blocking the slag discharge pipe, reducing the sand removal efficiency, and it is not convenient for later cleaning, so the practicability is poor. Content of the Utility Model

[0004] In order to solve the above technical problems, the utility model provides a sand remover that can smoothly discharge the slag slurry and will not block the pipeline, and quickly filters the pulp through two groups of filter rotating cylinders with different rotation speeds, thereby improving the filtering efficiency and the efficiency of cleaning the slag slurry, and thus enhancing the practicability of a sand remover for pulp production.

[0005] A sand remover for pulp production of the utility model comprises a sand remover housing, a bottom plate, four groups of legs, a sleeve, a first gear ring, a first rotating cylinder and a second rotating cylinder. The bottom end of the sand remover housing is connected to the bottom plate, the bottom end of the bottom plate is connected to four groups of legs, the left end and the right end of the sand remover housing are respectively provided with a discharge pipe, the bottom end of the sand remover housing is provided with a slag discharge pipe, the slag discharge pipe is hermetically penetrated through the bottom end of the bottom plate, a chamber is arranged inside the sand remover housing, a cover plate assembly is arranged at the top end of the sand remover housing, a feed pipe is arranged at the top end of the cover plate assembly, the top end of the bottom plate is connected to a bracket assembly, an electric cylinder is arranged on the bracket assembly, a rotating assembly is arranged at the top end of the sand remover housing, the top end of the sleeve is connected to the first gear ring, the sleeve is hermetically penetrated through the bottom end of the cover plate assembly by a bearing, the first gear ring is meshed with the rotating assembly in a tooth surface manner, a block assembly is arranged at the bottom end of the electric cylinder, slag discharge ports are respectively arranged at the left end and the right end of the sleeve, first filter screen through grooves and second filter screen through grooves are respectively arranged on the outer walls of the first rotating cylinder and the second rotating cylinder, a first through port is arranged at the bottom end of the first rotating cylinder, the first through port is sleeved and connected with the sleeve, a second through port is arranged at the bottom end of the second rotating cylinder, the second through port is sleeved and connected with the slag discharge pipe, the first rotating cylinder and the second rotating cylinder are meshed with each other in a tooth surface manner through a planetary gear assembly, two groups of clamping frames are respectively arranged on the inner wall of the chamber, and the bottom ends of the two groups of clamping frames are respectively in sliding contact with the first rotating cylinder and the second rotating cylinder.

[0006] Preferably, the support assembly includes four groups of first support rods, a first support plate, four groups of first screws, four groups of second support rods, and a disc. The top end of the bottom plate is connected to the four groups of first support rods. Four fixed threaded holes are provided at the top ends of the four groups of first support rods. Four fixed through holes are provided at the top end of the first support plate. The four groups of first screws are respectively threadedly connected to the fixed threaded holes through the fixed through holes. A third through port is provided at the top end of the first support plate. The top of the desander housing passes through the third through port. The bottom end of the first support plate is in close contact with the support table. The top end of the first support plate is connected to the four groups of second support rods. The top ends of the four groups of second support rods are connected to the disc. The top end of the disc is connected to the electric cylinder. A pneumatic rod is provided at the bottom end of the electric cylinder. The pneumatic rod slides out of the bottom end of the second support plate. The feed pipe slides out of the top end of the disc.

[0007] Preferably, the cover plate assembly includes a cover plate and four groups of second screws. Four mounting threaded holes are provided at the top end of the desander housing. Four mounting through holes are provided at the top end of the cover plate. The four groups of second screws are respectively threadedly connected to the mounting threaded holes through the mounting through holes.

[0008] Preferably, the rotating assembly includes four groups of third support rods, a second support plate, a reduction motor, and a first spur gear. The top end of the cover plate is connected to the four groups of third support rods. The top ends of the four groups of third support rods are connected to the second support plate. The top end of the second support plate is connected to the reduction motor. The output end of the reduction motor is sealed by a bearing and passes through the bottom end of the second support plate. The output end of the reduction motor is connected to the first spur gear. The first spur gear meshes with the tooth surface of the first spur gear.

[0009] Preferably, the planetary gear assembly includes a rotating box, three groups of second spur gears, three groups of rotating rods, a second gear ring, and six groups of fourth support rods. A rotating groove is provided at the top end of the rotating box. A toothed ring is provided on the outer wall of the rotating groove. The toothed ring meshes with the tooth surfaces of the three groups of second spur gears. The bottom ends of the three groups of second spur gears are respectively connected to the rotating rods. The bottom ends of the three groups of rotating rods are respectively connected to the rotating groove by bearings. The bottom end of the first rotating cylinder is connected to the second gear ring. The inner wall of the second gear ring is slidably sleeved on the inner wall of the rotating groove. The second gear ring meshes with the tooth surfaces of the three groups of second spur gears. Two clamping circular grooves are provided at the bottom end of the first rotating cylinder. Both of the two clamping circular grooves are clamped to the top end of the rotating box. The outer wall of the rotating box is respectively connected to the six groups of fourth support rods. The outer walls of the six groups of fourth support rods are respectively connected to the inner ends of the second rotating cylinder.

[0010] Preferably, the blocking block assembly includes a first blocking block, a fixing rod, and a second blocking block. The bottom end of the pneumatic rod is connected to the first blocking block. The first blocking block is slidably sleeved with the sleeve. The bottom end of the first blocking block is connected to the fixing rod. The bottom end of the fixing rod is connected to the second blocking block. The second blocking block is slidably sleeved with the slag discharge pipe.

[0011] Preferably, the top end of the second blocking block is provided as an inclined surface.

[0012] Preferably, the four sets of installation through holes and the four sets of fixing through holes are both set as counterbores.

[0013] Compared with the prior art, the beneficial effects of the present utility model are as follows: First, place the sand remover in a suitable position, then connect the feed pipe to the upper-level device. After that, the pulp enters the chamber. Then, start the rotating assembly to drive the first rotating cylinder to rotate. After that, the first rotating cylinder drives the second rotating cylinder to rotate through the planetary gear assembly. In this way, larger sundries in the pulp are removed through the first rotating cylinder, and smaller slag pulp is removed through the second rotating cylinder. The pulp after slag removal will be discharged through the discharge pipe. Then, when it is necessary to discharge the stones, sand, and sundries in the two rotating cylinders, the electric cylinder drives the plug component to move upward, so that the slag pulp is discharged into the slag discharge pipe through the first through port and the second through port, thereby improving the filtration efficiency and the efficiency of cleaning the slag pulp, and thus enhancing the practicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic connection structure diagram of the present utility model;

[0015] Figure 2 is a schematic connection structure diagram of the first support plate and the second support rod of the present utility model;

[0016] Figure 3 is a schematic connection structure diagram of the fixing rod and the second plug of the present utility model;

[0017] Figure 4 is a schematic enlarged partial structure diagram A of the present utility model;

[0018] Reference numerals in the drawings: 1. Sand remover housing; 2. Bottom plate; 3. Legs; 4. Discharge pipe; 5. Slag discharge pipe; 6. Chamber; 7. Feed pipe; 8. Electric cylinder; 9. Sleeve; 10. First gear ring; 11. First rotating cylinder; 12. Second rotating cylinder; 13. Mounting frame; 14. First support rod; 15. First support plate; 16. First screw; 17. Second support rod; 18. Disc; 19. Pneumatic rod; 20. Cover plate; 21. Second screw; 22. Third support rod; 23. Second support plate; 24. Reduction motor; 25. First spur gear; 26. Rotating box; 27. Tooth ring; 28. Second spur gear; 29. Rotating rod; 30. Second gear ring; 31. Fourth support rod; 32. First plug; 33. Fixing rod; 34. Second plug. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following combines the drawings and embodiments to further describe in detail the specific embodiments of the present utility model. The following embodiments are used to illustrate the present utility model, but are not used to limit the scope of the present utility model.

[0020] As Figures 1 to 4 shown, a desander for pulp production of the present utility model includes a desander housing 1, a bottom plate 2, four sets of legs 3, a sleeve 9, a first gear ring 10, a first rotating cylinder 11 and a second rotating cylinder 12. The bottom end of the desander housing 1 is connected to the bottom plate 2, the bottom end of the bottom plate 2 is connected to the four sets of legs 3. The left end and the right end of the desander housing 1 are respectively provided with discharge pipes 4. The bottom end of the desander housing 1 is provided with a slag discharge pipe 5, and the slag discharge pipe 5 hermetically penetrates through the bottom end of the bottom plate 2. A chamber 6 is arranged inside the desander housing 1. A cover plate assembly is arranged at the top end of the desander housing 1, and a feed pipe 7 is arranged at the top end of the cover plate assembly. The top end of the bottom plate 2 is connected to a support assembly, an electric cylinder 8 is arranged on the support assembly. A rotating assembly is arranged at the top end of the desander housing 1. The top end of the sleeve 9 is connected to the first gear ring 10, and the sleeve 9 is hermetically penetrated through the bottom end of the cover plate assembly by a bearing. The first gear ring 10 is meshed with the rotating assembly in a tooth surface manner. A plug block assembly is arranged at the bottom end of the electric cylinder 8. Discharge ports are respectively arranged at the left end and the right end of the sleeve 9. First filter screen through grooves and second filter screen through grooves are respectively arranged on the outer walls of the first rotating cylinder 11 and the second rotating cylinder 12. A first through port is arranged at the bottom end of the first rotating cylinder 11, and the first through port is sleeved and connected with the sleeve 9. A second through port is arranged at the bottom end of the second rotating cylinder 12, and the second through port is sleeved and connected with the slag discharge pipe 5. The first rotating cylinder 11 and the second rotating cylinder 12 are meshed with each other in a tooth surface manner through a planetary gear assembly. Two sets of clamping frames 13 are respectively arranged on the inner wall of the chamber 6, and the bottom ends of the two sets of clamping frames 13 are respectively in sliding contact with the first rotating cylinder 11 and the second rotating cylinder 12; First, place the desander in a suitable position, then connect the feed pipe to the upper device. After that, the pulp enters the chamber. Then start the rotating assembly to drive the first rotating cylinder to rotate. After that, the first rotating cylinder drives the second rotating cylinder to rotate through the planetary gear assembly. In this way, larger sundries in the pulp are removed through the first rotating cylinder, and smaller slag slurries are removed through the second rotating cylinder. The deslagged pulp will be discharged through the discharge pipe. Then, when it is necessary to discharge the stones, sand and sundries in the two rotating cylinders, drive the plug block assembly to move upward by the electric cylinder, so as to discharge the slag slurry into the slag discharge pipe through the first through port and the second through port, thereby improving the filtration efficiency and the efficiency of cleaning the slag slurry, and thus enhancing the practicability.

[0021] Preferably, as in the above embodiments, the support assembly includes four groups of first support rods 14, a first support plate 15, four groups of first screws 16, four groups of second support rods 17, and a disc 18. The top of the bottom plate 2 is connected to the four groups of first support rods 14. Four fixed threaded holes are provided at the tops of the four groups of first support rods 14. Four fixed through holes are provided at the top of the first support plate 15. The four groups of first screws 16 are respectively threadedly connected to the fixed threaded holes through the fixed through holes. A third through port is provided at the top of the first support plate 15. The top of the sand remover housing 1 passes through the third through port. The bottom of the first support plate 15 is in close contact with the support table. The top of the first support plate 15 is connected to the four groups of second support rods 17. The tops of the four groups of second support rods 17 are connected to the disc 18. The top of the disc 18 is connected to the electric cylinder 8. A pneumatic rod 19 is provided at the bottom of the electric cylinder 8. The pneumatic rod 19 slides out of the bottom of the second support plate 23. The feed pipe 7 slides out of the top of the disc 18. The connection between the first support plate and the four support rods can be achieved through the four groups of first screws, thereby installing the four groups of second support rods and the disc, and then installing the electric cylinder, thus enhancing the practicality.

[0022] Preferably, as in the above embodiments, the cover assembly includes a cover 20 and four groups of second screws 21. Four mounting threaded holes are provided at the top of the sand remover housing 1. Four mounting through holes are provided at the top of the cover 20. The four groups of second screws 21 are respectively threadedly connected to the mounting threaded holes through the mounting through holes. The installation of the cover can be achieved through the four groups of second screws, which facilitates the subsequent cleaning of the slurry in the chamber, thus enhancing the practicality.

[0023] Preferably, as in the above embodiments, the rotating assembly includes four groups of third support rods 22, a second support plate 23, a reduction motor 24, and a first spur gear 25. The top of the cover 20 is connected to the four groups of third support rods 22. The tops of the four groups of third support rods 22 are connected to the second support plate 23. The top of the second support plate 23 is connected to the reduction motor 24. The output end of the reduction motor 24 is sealed through the bearing at the bottom of the second support plate 23. The output end of the reduction motor 24 is connected to the first spur gear 25. The first spur gear 25 is in meshing engagement with the first spur gear 25. The first spur gear can be rotated by the reduction motor, thereby driving the first gear ring and the sleeve to rotate through the first spur gear, and then driving the first rotating cylinder to rotate, thus enhancing the practicality.

[0024] Preferably, as in the above embodiment, the planetary gear assembly includes a rotating box 26, three groups of second planar gears 28, three groups of rotating rods 29, a second gear ring 30, and six groups of fourth support rods 31. A rotating groove is provided at the top of the rotating box 26, and a toothed ring 27 is provided on the outer wall of the rotating groove. The toothed ring 27 is in meshing engagement with the tooth surfaces of the three groups of second planar gears 28. The bottoms of the three groups of second planar gears 28 are respectively connected to the rotating rods 29, and the bottoms of the three groups of rotating rods 29 are respectively connected to the rotating groove by bearings. The bottom end of the first rotating cylinder 11 is connected to the second gear ring 30. The inner wall of the second gear ring 30 is slidably sleeved on the inner wall of the rotating groove. The second gear ring 30 is in meshing engagement with the tooth surfaces of the three groups of second planar gears 28. Two clamping circular grooves are provided at the bottom end of the first rotating cylinder 11, and both of the two clamping circular grooves are clamped with the top of the rotating box 26. The outer wall of the rotating box 26 is respectively connected to the six groups of fourth support rods 31, and the outer walls of the six groups of fourth support rods 31 are respectively connected to the inner ends of the second rotating cylinder 12; when the first rotating cylinder rotates, it drives the second gear ring to rotate, and then drives the rotating box and the second rotating cylinder connected by the six groups of fourth support rods to rotate through the three groups of second planar gears, thereby enhancing the practicability.

[0025] Preferably, as in the above embodiment, the plug block assembly includes a first plug block 32, a fixing rod 33, and a second plug block 34. The bottom end of the pneumatic rod 19 is connected to the first plug block 32. The first plug block 32 is slidably sleeved on the sleeve 9. The bottom end of the first plug block 32 is connected to the fixing rod 33, and the bottom end of the fixing rod 33 is connected to the second plug block 34. The second plug block 34 is slidably sleeved on the slag discharge pipe 5; the pneumatic rod can drive the first plug block and the second plug block to move up and down, so as to open the two slag discharge ports and the slag discharge pipe, thereby enhancing the practicability.

[0026] Preferably, the top of the second plug block 34 is provided as an inclined surface; by providing the top of the second plug block as an inclined surface for guiding the slag slurry, the practicability is enhanced.

[0027] Preferably, the four mounting through holes and the four fixing through holes are all provided as counterbores; the four first screws and the four second screws can be hidden through the counterbores, thereby enhancing the practicability.

[0028] A desander for pulp production according to the present utility model has the following working principle. During operation, first place the desander in a suitable position, then connect the feed pipe to the upper-level device. After that, the pulp enters the chamber. Then start the reduction motor to drive the first planar gear and the first gear ring to rotate. Subsequently, drive the sleeve to rotate through the first gear ring. Then, when the first rotating cylinder rotates, impurities in the pulp are removed. Next, when the first rotating cylinder rotates, it drives the second gear ring to rotate. Then, drive the rotating box and the second rotating cylinder to rotate through three groups of second planar gears. In this way, larger impurities in the pulp are removed by the first rotating cylinder, and smaller slag is removed by the second rotating cylinder. The deslagged pulp is discharged through the discharge pipe. Then, when it is necessary to discharge the stones, sand, and impurities in the two rotating cylinders, drive the two plug blocks to move upward by the electric cylinder to open the two slag discharge ports and the slag discharge pipes. After that, the slag pulp is discharged into the slag discharge pipes through the first through hole and the second through hole. Then, when it is necessary to clean and repair the equipment in the chamber, first remove the four first screws, then remove the disc, the electric cylinder, the two plug blocks, and the first support plate. Then, remove the cover plate by the four second screws. After removing the cover plate, the sleeve and the first rotating cylinder will be driven down, and then the maintenance and repair in the chamber can be carried out. After the maintenance and repair are completed, reinstall the sleeve, the first rotating cylinder, and the cover plate with the four second screws, and then reinstall the support frame assembly with the four first screws.

[0029] The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0030] In the present utility model, the terms "first", "second", "third" do not represent specific quantities and sequences, but are only used for name distinction.

[0031] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the technical principle of the present utility model, several improvements and modifications can still be made, and these improvements and modifications should also be regarded as the protection scope of the present utility model.

Claims

1. A desander for pulp production, characterized in that, It includes a desander housing (1), a bottom plate (2), four sets of legs (3), a sleeve (9), a first gear ring (10), a first rotating cylinder (11) and a second rotating cylinder (12). The bottom end of the desander housing (1) is connected to the bottom plate (2), the bottom end of the bottom plate (2) is connected to the four sets of legs (3). Discharge pipes (4) are respectively arranged at the left and right ends of the desander housing (1). A slag discharge pipe (5) is arranged at the bottom end of the desander housing (1), and the slag discharge pipe (5) hermetically penetrates through the bottom end of the bottom plate (2). A chamber (6) is arranged inside the desander housing (1). A cover plate assembly is arranged at the top end of the desander housing (1), and a feed pipe (7) is arranged at the top end of the cover plate assembly. The top end of the bottom plate (2) is connected to a support assembly, an electric cylinder (8) is arranged on the support assembly. A rotating assembly is arranged at the top end of the desander housing (1). The top end of the sleeve (9) is connected to the first gear ring (10), the sleeve (9) hermetically passes through the bottom end of the cover plate assembly by means of bearings. The first gear ring (10) is in meshing with the rotating assembly on the tooth surface. A block assembly is arranged at the bottom end of the electric cylinder (8). Slag discharge ports are respectively arranged at the left and right ends of the sleeve (9). First filter screen through grooves and second filter screen through grooves are respectively arranged on the outer walls of the first rotating cylinder (11) and the second rotating cylinder (12). A first through port is arranged at the bottom end of the first rotating cylinder (11), and the first through port is sleeved and connected with the sleeve (9). A second through port is arranged at the bottom end of the second rotating cylinder (12), and the second through port is sleeved and connected with the slag discharge pipe (5). The first rotating cylinder (11) and the second rotating cylinder (12) are in meshing with each other on the tooth surface through a planetary gear assembly. Two sets of clamping frames (13) are respectively arranged on the inner wall of the chamber (6), and the bottom ends of the two sets of clamping frames (13) are respectively in sliding and close contact with the first rotating cylinder (11) and the second rotating cylinder (12).

2. The desander for pulp production according to claim 1, characterized in that, The support assembly includes four sets of first support rods (14), a first support plate (15), four sets of first screws (16), four sets of second support rods (17) and a disc (18). The top end of the bottom plate (2) is connected to the four sets of first support rods (14). Four sets of fixed threaded holes are arranged at the top ends of the four sets of first support rods (14). Four sets of fixed through holes are arranged at the top end of the first support plate (15). The four sets of first screws (16) are respectively threadedly connected to the fixed threaded holes through the fixed through holes. A third through port is arranged at the top end of the first support plate (15), and the top of the desander housing (1) passes through the third through port. The bottom end of the first support plate (15) is in close contact with a support table. The top end of the first support plate (15) is connected to the four sets of second support rods (17), the top ends of the four sets of second support rods (17) are connected to the disc (18). The top end of the disc (18) is connected to the electric cylinder (8). A pneumatic rod (19) is arranged at the bottom end of the electric cylinder (8), and the pneumatic rod (19) slidably passes through the bottom end of the second support plate (23). The feed pipe (7) slidably passes through the top end of the disc (18).

3. The desander for pulp production according to claim 2, characterized in that, The cover plate assembly includes a cover plate (20) and four groups of second screws (21). At the top of the desander housing (1), there are four groups of mounting threaded holes. At the top of the cover plate (20), there are four groups of mounting through holes. The four groups of second screws (21) are respectively threadedly connected to the mounting threaded holes through the mounting through holes.

4. The desander for pulp production according to claim 3, characterized in that, The rotating assembly includes four groups of third support rods (22), a second support plate (23), a reduction motor (24), and a first spur gear (25). The top of the cover plate (20) is connected to the four groups of third support rods (22). The tops of the four groups of third support rods (22) are connected to the second support plate (23). The top of the second support plate (23) is connected to the reduction motor (24). The output end of the reduction motor (24) is sealed by a bearing and passes through the bottom of the second support plate (23). The output end of the reduction motor (24) is connected to the first spur gear (25). The first spur gear (25) meshes with the tooth surface of the first spur gear (25).

5. The desander for pulp production according to claim 4, characterized in that, The planetary gear assembly includes a rotating box (26), three groups of second spur gears (28), three groups of rotating rods (29), a second gear ring (30), and six groups of fourth support rods (31). At the top of the rotating box (26), there is a rotating groove. On the outer wall of the rotating groove, there is a toothed ring (27). The toothed ring (27) meshes with the tooth surfaces of the three groups of second spur gears (28). The bottoms of the three groups of second spur gears (28) are respectively connected to the rotating rods (29). The bottoms of the three groups of rotating rods (29) are respectively connected to the rotating groove by bearings. The bottom of the first rotating cylinder (11) is connected to the second gear ring (30). The inner wall of the second gear ring (30) is slidably sleeved on the inner wall of the rotating groove. The second gear ring (30) meshes with the tooth surfaces of the three groups of second spur gears (28). At the bottom of the first rotating cylinder (11), there are two clamping circular grooves. Both of the two clamping circular grooves are clamped with the top of the rotating box (26). The outer wall of the rotating box (26) is respectively connected to the six groups of fourth support rods (31). The outer walls of the six groups of fourth support rods (31) are respectively connected to the inner ends of the second rotating cylinder (12).

6. The desander for pulp production according to claim 5, characterized in that, The plug block assembly includes a first plug block (32), a fixing rod (33), and a second plug block (34). The bottom of the pneumatic rod (19) is connected to the first plug block (32). The first plug block (32) is slidably sleeved on the sleeve (9). The bottom of the first plug block (32) is connected to the fixing rod (33). The bottom of the fixing rod (33) is connected to the second plug block (34). The second plug block (34) is slidably sleeved on the slag discharge pipe (5).

7. The desander for pulp production according to claim 6, characterized in that, The top of the second plug block (34) is set to be an inclined surface.

8. The desander for pulp production according to claim 7, characterized in that, The four groups of mounting through holes and the four groups of fixing through holes are both set to be counterbored holes.

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