Labyrinth seal for a roller press mechanism of a dry granulator

Abstract

The application discloses a labyrinth seal of a roller pressing mechanism of a dry granulator, which comprises a roller shaft, a bearing seat and a roller pressing box body, the labyrinth seal is arranged between the roller pressing box body and the bearing seat on the roller shaft, and comprises a positioning ring, an inner seal, a middle seal, a gland and an outer seal; the inner seal and the middle seal are both rotary skeleton seals, and are respectively sleeved in stepped holes of the positioning ring in an interference fit mode and are in interference fit with the roller shaft; and the outer seal is sleeved in a second counterbore of the gland in an interference fit mode and is in interference fit with the roller shaft; the labyrinth seal adopts three seals, i.e., an outer seal, a middle seal and an inner seal, and a total of 7 groups of lip dynamic seals; the inner skeleton and the outer skeleton of the middle seal and the skeleton of the inner seal are all subjected to rubber coating treatment, so that all joint surfaces are sealed; the multiple seals greatly improve the sealing effect, prolong the service life of the sealing structure, effectively prevent the contamination of driving mechanisms and the contamination of external environments in the process of tabletting of powder raw materials, prevent the contamination of powder raw materials by external microorganisms, and ensure the quality of granulation products.

Description

Technical Field

[0001] This invention relates to the field of dry granulation machine technology, and more particularly to a labyrinth seal for a dry granulation machine roller pressing mechanism. Background Technology

[0002] Currently, most dry granulation mills use a common single-set lip dynamic sealing structure for their roller pressing mechanism. Under long-term operation, this results in poor sealing performance, and the sealing lip is prone to wear and failure during operation. Because this failure is difficult to detect and lacks warning, it can easily lead to equipment damage and increased maintenance costs. Wear and failure of the sealing lip also allows powder material to seep into and remain on the drive mechanism, contaminating it, making it difficult to clean, and increasing the risk of cross-contamination by microorganisms, affecting product consistency. Furthermore, wear and failure of the sealing lip can allow external microorganisms to enter the granulation space and contaminate the powder material. Finally, wear and failure of the sealing lip can also allow powder material to enter the external environment, contaminating it and causing harm to the operator. Summary of the Invention

[0003] To address the problems of wear and failure of existing single-unit lip dynamic seal structures in dry granulation machines, which can damage equipment, contaminate the drive mechanism and external environment, and cause cross-contamination by microorganisms, thus affecting product quality, this invention provides a labyrinth seal for the roller pressing mechanism of a dry granulation machine. This labyrinth seal is installed on both the left and right sides of the roller pressing box on the roller shaft, significantly improving the sealing effect, extending the sealing lip's failure time, and increasing the service life of the sealing structure. A moisture sensor is inserted into the warning sealing cavity to monitor its resistance value in real time. A sharp drop in the resistance value of the moisture sensor to 0.1RΩ indicates moisture intrusion inside the sealing cavity, warning of failure of the outer and middle seals. This information is immediately sent to the control system of the dry granulation machine, which will immediately stop the equipment and replace the outer and middle seals, thereby solving the aforementioned technical problems.

[0004] To achieve the above objectives, the present invention provides a labyrinth seal for a dry granulation mill roller pressing mechanism, comprising a roller shaft, a bearing housing, and a roller pressing box. The bearing housing is located at the right end of the roller shaft and contains a supporting bearing. A first step is provided on the outer circumference of the roller shaft corresponding to the position of the supporting bearing. The inner ring of the supporting bearing is fastened to the outer circumference of the first step, and the outer ring is fastened to the inner circumference of the bearing housing. The other end of the roller shaft passes through the roller pressing box. The labyrinth seal is located between the roller pressing box and the bearing housing on the roller shaft and includes a positioning ring, an inner seal, a middle seal, a pressure cap, and an outer seal. The positioning ring is fitted between the bearing housing on the roller shaft and the right side panel of the roller pressing box. A first flange extending outward is provided on the outer circumference of the right end. An outer stop is provided on the right end face of the first flange. The outer stop is inserted into the inner hole of the bearing housing and fits against the end face of the outer ring of the supporting bearing. The right end face of the first flange is sealed and fixedly connected to the left end face of the bearing housing. A first through hole is provided inside the positioning ring. The first through hole has a first countersunk hole on its right side, and a first layer hole and a second layer hole on its left side. The diameter of the second layer hole is larger than that of the first layer hole. The inner seal is fitted with an interference fit inside the first layer hole, with its right end face close to the right end face of the first layer hole, located at the right end of the positioning ring. The middle seal is fitted with an interference fit inside the second layer hole, with its right end face close to the right end face of the second layer hole, located at the left end of the positioning ring. The positioning ring, inner seal, and middle seal form a component that is fitted onto the roller shaft. Both the inner seal and the middle seal are fitted with the roller shaft. The left end of the positioning ring is inserted into the box panel, with its left end face aligned with the left side of the box panel. The pressure cap has a second through hole, and a second countersunk hole is provided on the right side of the second through hole. The outer seal is fitted with an interference fit inside the second countersunk hole, forming a component with the pressure cap that is fitted onto the roller shaft. The outer seal is fitted with the roller shaft. The right end face of the pressure cap is sealed and fixedly connected to the left end face of the positioning ring and the left side of the box panel.

[0005] The outer sealing lip is provided at the left end of the inner diameter of the outer seal and faces to the left. The outer sealing lip is interference-fitted with the outer surface of the roller.

[0006] The roller shaft has a second step corresponding to the second layer hole for positioning the middle seal. The middle seal includes an inner skeleton, a labyrinth seal body, and an outer skeleton. The inner skeleton has two 90-degree rightward bends, one upper and one lower, which are parallel to the roller shaft. The inner diameter of the lower bend is interference-fitted with the outer circular surface of the second step of the roller shaft. The outer side of the inner skeleton has a layer of inner skeleton rubber coating, which extends and covers the junction between the inner skeleton and the roller shaft, forming a seal at that point. The labyrinth seal body is located between the inner skeleton and the outer skeleton and has multiple middle seal lips, which are interference-fitted with the inner side of the inner skeleton. The upper end of the outer skeleton has a 90-degree leftward bend, and the outer side of this bend has a layer of outer skeleton rubber coating, which covers the junction between the outer skeleton and the inner circular surface of the second layer hole, forming a seal at that point. The outer skeleton rubber coating and the labyrinth seal body are connected as an integral structure.

[0007] The inner seal includes an inner seal skeleton and an inner seal body. The inner seal body has a left inner seal lip facing left at its left end and a right inner seal lip facing right at its right end. Both the left and right inner seal lips are interference-fitted with the corresponding outer circular surfaces of the roller shaft. The inner seal skeleton is located inside the inner seal body. The inner seal skeleton is covered with a skeleton rubber coating. The skeleton rubber coating covers the inner circumferential surface where the inner seal skeleton and the positioning ring connect, forming a seal on the inner circumferential surface at the connection. The skeleton rubber coating and the inner seal body are connected as an integral structure.

[0008] As a further improvement to this technology, a radially threaded hole is provided in the middle of the outer wall of the positioning ring. This threaded hole communicates with the first layer hole. A moisture sensor is threadedly connected to the inner wall of the threaded hole. The moisture sensor and the positioning ring are statically sealed by an O-ring. The moisture sensor is a resistance monitoring sensor. The sensing head of the moisture sensor consists of two wires. A warning sealing cavity is formed between the inner wall of the first layer hole of the positioning ring, the outer surface of the roller, the inner seal, and the middle seal. The sensing head extends into the warning sealing cavity and monitors the resistance value of the moisture sensor in the warning sealing cavity in real time as a warning indicator of seal failure. When the warning sealing cavity is dry and free of moisture intrusion, the normal operating resistance value of the moisture sensor is RΩ. However, when moisture is present in the warning sealing cavity, the two wires of the moisture sensor are connected, and its resistance decreases sharply and instantaneously. When it drops below 0.1RΩ, it indicates that the outer seal and the middle seal have failed. The dry granulation machine control system will issue a warning, control the equipment to stop running, and promptly replace the outer seal and the middle seal.

[0009] As a further improvement to this technology, the central sealing opening includes a first vertical sealing lip, a second vertical sealing lip, and a horizontal sealing lip. The first and second vertical sealing lips are respectively opened on the vertical inner surface of the labyrinth-type sealing body at the top and bottom. The first and second vertical sealing lips are interference-fitted with the inner side of the vertical side of the inner skeleton. The right end of the inner diameter of the labyrinth-type sealing body is provided with a horizontal sealing lip facing the right, which is interference-fitted with the outer diameter of the lower bent side of the inner skeleton.

[0010] As a further improvement to this technology, the labyrinth-type sealing body is also provided with a cup-shaped lip, which is located above the first vertical sealing lip on the same side, forming a non-contact seal with the bent edge on the inner skeleton.

[0011] As a further improvement to this technology, grease is applied to the cavities formed by the outer sealing lip, the inner left sealing lip, the inner right sealing lip and the roller shaft mating surfaces to form a grease diaphragm, which is used to alleviate frictional wear between the outer sealing lip, the inner left sealing lip, the inner right sealing lip and the roller shaft; grease is also applied to the cavities formed by the first vertical sealing lip, the second vertical sealing lip, the horizontal sealing lip and the inner skeleton mating surfaces to form a grease diaphragm, which is used to alleviate frictional wear between the first vertical sealing lip, the second vertical sealing lip, the horizontal sealing lip and the inner skeleton.

[0012] As a further improvement to this technology, the axial distance L1 between the cavity formed by the outer seal and the middle seal is set to 15-20 mm, and the axial distance L2 between the cavity formed by the middle seal and the inner seal is set to 40-45 mm.

[0013] As a further improvement to this technology, an annular sealing groove is provided on the right end face of the first flange of the positioning ring, and an O-ring is provided in the annular sealing groove. The right end face of the first flange is sealed and fitted with the left end face of the bearing seat, and is fixedly connected by multiple locking bolts.

[0014] As a further improvement to this technology, a sealing ring and a pressure ring are provided between the right end face of the pressure cap and the left side face of the roller pressing box and the left end face of the positioning ring. The sealing ring is sleeved on the roller shaft. A gap is left between the inner circular surface of the roller shaft through hole of the box panel and the outer circular surface of the positioning ring. A right-protruding annular n-shaped sealing ring is provided in the middle of the sealing ring. The annular n-shaped sealing ring is inserted into the gap. The right end face of the outer ring of the sealing ring is in contact with the left side face of the box panel, and the right end face of the inner ring is in contact with the left end face of the positioning ring. The pressure ring is sleeved on the roller shaft, with its right end face fitting against the left end face of the outer ring of the sealing ring. The pressure ring and the sealing ring are fixedly connected to the box panel by a number of second clamping screws. The right end face of the pressure cover is fitted against the left end face of the inner ring of the sealing ring, and is fixedly connected to the sealing ring and the positioning ring by a number of first clamping screws. A second flange extending outward is provided on the outer circular surface of the left end of the pressure cover. An elastic sliding pad is fixedly connected to the right end face of the second flange, and the right end face of the elastic sliding pad is fitted against the left end face of the pressure ring.

[0015] This invention also provides a method for early warning of seal failure of the labyrinth seal of the roller pressing mechanism of the above-mentioned dry granulator, characterized by including the following steps:

[0016] S1. Seal Failure Warning: During normal operation, the moisture sensor's resistance is RΩ. The lower warning limit resistance is set to 0.1RΩ in the granulator's control system. The dry granulator's operation involves rolling powder into sheets. Processing is done in batches, and operators need to regularly clean the powder inside the roller press chamber and then rinse it with clean water. This is especially important when the powder composition differs between batches. After each batch is processed, the roller press chamber must be cleaned and rinsed. As the dry granulator operates... As the outer sealing lip, the first vertical sealing lip, the second vertical sealing lip, and the horizontal sealing lip gradually wear down, the loss of interference fit due to wear leads to sealing failure. When cleaning the roller press box, moisture and dust will enter the sealed cavity formed by each sealing lip in sequence from the outside to the inside as each sealing lip fails, until it enters the warning sealing cavity. This causes the moisture sensor to detect a sudden and sharp decrease in its resistance. When the resistance drops below 0.1RΩ, it indicates that the outer and middle seals have failed, and the dry granulator control system will issue a warning and stop the equipment from running.

[0017] S2. Handling of seal failure: Disassemble and inspect the labyrinth seal structure. Use a microscope to observe the wear of the outer sealing lip, the first vertical sealing lip, the second vertical sealing lip, the horizontal sealing lip, the left inner sealing lip, and the right inner sealing lip. Use a dimensional measuring instrument to check the interference δ between the outer sealing lip, the first vertical sealing lip, the second vertical sealing lip, the horizontal sealing lip, the left inner sealing lip, and the right inner sealing lip and their corresponding mating surfaces. Replace the outer seal and the middle seal in a timely manner.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. The labyrinth seal of this invention employs three seals: outer, middle, and inner, with a total of seven sets of dynamic lip seals. Both the middle and inner seals utilize rotating skeleton seals. The inner skeleton, outer skeleton, and inner sealing skeleton of the middle seal are all coated with rubber, covering the mating surfaces of the skeleton with the inner wall of the positioning ring and the outer circular surface of the roller. An O-ring seal is used between the positioning ring and the bearing seat connection surface. A sealing ring seal is used between the pressure cap and the housing panel and the positioning ring. The multiple seals greatly improve the sealing effect, enhance the reliability of the seal, and extend the service life of the labyrinth seal. This effectively prevents dust from the powder raw material from contaminating the drive mechanism during the powder raw material tableting and granulation process. At the same time, it blocks the connection between the external environment and the dust in the granulation space, preventing dust from contaminating the external environment and controlling the contamination of dust by external microorganisms, thereby ensuring the quality of the granulated product.

[0020] 2. This invention employs a moisture sensor. The sensing head is inserted into the warning sealed cavity. When the warning sealed cavity is dry and free of moisture, the normal operating resistance of the moisture sensor is RΩ. However, when moisture is present in the warning sealed cavity, the two wires of the moisture sensor are connected, and its resistance decreases sharply and instantaneously. When it drops below 0.1RΩ, it indicates that the outer and middle seals have failed. The moisture sensor sends the seal failure information to the control system, which can immediately know about the seal failure, stop the equipment operation immediately, and promptly handle and replace the worn seals that have caused the seal failure, thereby extending the service life of the equipment and saving equipment maintenance costs. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention. Figure 4 (Magnified at point I);

[0022] Figure 2 This is a schematic diagram of the sealing structure of the inner seal, middle seal, and outer seal, as well as the rubber-coated skeleton, in an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the labyrinth-type sealing installation structure according to an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the positioning ring structure according to an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of the cap structure according to an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the sealing principle in an embodiment of the present invention (illustration of dust and moisture intrusion due to seal failure);

[0027] Figure 7This is a graph showing the resistance value monitoring of the moisture sensor according to an embodiment of the present invention.

[0028] In the diagram: 1. Roller; 101. First step; 102. Second step; 2. Positioning ring; 201. First flange; 202. Outer stop; 203. First through hole; 204. First layer hole; 205. Second layer hole; 206. Threaded hole; 207. Annular sealing groove; 208. First countersunk hole; 3. Inner seal; 301. Inner seal body; 3011. Left lip of inner seal; 3012. Right lip of inner seal; 302. Inner seal skeleton; 3021. Skeleton coating; 4. Middle seal; 401. Outer skeleton; 4011. Outer skeleton coating; 402. Inner skeleton; 4021. Inner skeleton coating; 403. Labyrinth seal body 4031. Cup-shaped lip; 4032. First vertical sealing port; 4033. Second vertical sealing port; 4034. Horizontal sealing lip; 5. Outer seal; 501. Outer sealing lip; 6. Powder roller pressing working area; 7. Pressure cap; 701. Second through hole; 702. Second countersunk hole; 703. Second flange; 8. Sealing ring; 9. Moisture sensor; 901. Wire; 10. Roller pressing box; 1001. Box panel; 11. Bearing seat; 12. Roller support bearing; 13. Elastic sliding pad; 14. Pressure ring; 15. Lubricating grease; 16. Early warning sealing cavity; 17. O-ring seal; 18. Powder particles; 19. Moisture particles. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] like Figures 1 to 5As shown, this embodiment of the invention includes a roller shaft 1, a bearing housing 11, and a roller pressing box 10. The bearing housing 11 is located at the right end of the roller shaft 1 and has a supporting bearing 12 inside. A first step 101 is provided on the outer surface of the roller shaft 1 at a position corresponding to the supporting bearing 12. The inner ring of the supporting bearing 12 is fastened to the outer surface of the first step 101, and the outer ring is fastened to the inner surface of the bearing housing 11. The other end of the roller shaft 1 passes through the roller pressing box 10. A labyrinth seal is provided between the roller pressing box 10 and the bearing housing 11 on the roller shaft 1, including a positioning ring 2, an inner seal, and a middle seal 4. The pressure cap 7 and outer seal 5, and the positioning ring 2 are fitted between the bearing seat 11 on the roller shaft 1 and the right side panel 1001 of the roller pressing box 10. A first flange 201 extending outwards is provided on the outer circular surface of the right end. An outer stop 202 is provided on the right end face of the first flange 201, which is inserted into the inner hole of the bearing seat 11 and fits against the outer ring end face of the supporting bearing 12. The right end face of the first flange 201 is sealed and fixedly connected to the left end face of the bearing seat 11. A first through hole 203 is provided inside the positioning ring 2, and a second... A countersunk hole 208 is provided. On the left side, a first layer of holes 204 and a second layer of holes 205 are sequentially provided. The diameter of the second layer of holes 205 is larger than that of the first layer of holes 204. The inner seal 3 is interference-fitted into the first layer of holes 204, with its right end face pressed against the right end face of the first layer of holes 204, located at the right end of the positioning ring 2. The middle seal 4 is interference-fitted into the second layer of holes 205, with its right end face pressed against the right end face of the second layer of holes 205, located at the left end of the positioning ring 2. The positioning ring 2, the inner seal 3, and the middle seal 4 constitute a single component and are integrally fitted onto the roller shaft 1. Both the inner seal 3 and the middle seal 4 are interference-fitted with the roller 1. The left end of the positioning ring 2 is inserted into the box panel 10, and the left end face is aligned with the left side face of the box panel 1001. The pressure cover 7 has a second through hole 701, and a second countersunk hole 702 is provided on the right side of the second through hole 701. The outer circle of the outer seal 5 is interference-fitted into the second countersunk hole 702, and together with the pressure cover 7, they form a component that is integrally fitted onto the roller 1. The outer seal 5 is interference-fitted with the roller 1. The right end face of the pressure cover 7 is sealed and fixedly connected to the left end face of the positioning ring 2 and the left side face of the box panel 1001.

[0031] The outer seal 5 has an outer sealing lip 501 facing the left side at the upper left end of the inner diameter. The outer sealing lip 501 is interference-fitted with the outer circular surface of the roller 1.

[0032] A second step 102 is provided on the roller shaft 1 at a position corresponding to the second layer hole 205 for the installation and positioning of the middle seal 4. The middle seal 4 includes an inner skeleton 402, a labyrinth seal body 403, and an outer skeleton 401. The inner skeleton 402 has two 90-degree rightward bends, one upper and one lower, which are parallel to the roller shaft 1. The inner diameter of the lower bend is interference-fitted with the outer surface of the second step 102 of the roller shaft 1. An inner skeleton rubber coating 4021 is provided on the outside of the inner skeleton 402, and the inner skeleton rubber coating 4021 extends and covers the inner skeleton 402 to cooperate with the roller shaft 1. At the junction, a seal is formed. The labyrinth seal body 403 is located between the inner skeleton 402 and the outer skeleton 401. It has multiple middle sealing lips, which are all interference-fitted with the inner side of the inner skeleton 402. The upper end of the outer skeleton 401 has a left-bent edge bent at 90 degrees. A layer of outer skeleton adhesive 4011 is provided on the outside of the bent edge. The outer skeleton adhesive 4011 covers the junction between the outer skeleton 401 and the inner circular surface of the second layer hole 205, forming a seal. The outer skeleton adhesive 4011 and the labyrinth seal body 403 are connected as an integral structure.

[0033] The inner seal 3 includes an inner seal skeleton 302 and an inner seal body 301. The inner seal body 301 has an inner seal left lip 3011 facing the left side at the left end of its inner diameter and an inner seal right lip 3012 facing the right side at the right end. Both the inner seal left lip 3011 and the inner seal right lip 3012 are interference-fitted with the corresponding outer circular surface of the roller shaft 1. The inner seal skeleton 302 is located inside the inner seal body 301. The inner seal skeleton 302 is covered with a skeleton rubber 3021. The skeleton rubber 3021 covers the inner circumferential surface where the inner seal skeleton 302 and the positioning ring 2 are connected, forming a seal on the inner circumferential surface at the connection. The skeleton rubber 3021 and the inner seal body 301 are connected as an integral structure.

[0034] A radially threaded hole 206 is provided in the middle of the outer side wall of the positioning ring 2. The threaded hole 206 communicates with the first layer hole 204. A moisture sensor 9 is threadedly connected to the threaded hole 206. The moisture sensor 9 and the positioning ring 2 are statically sealed by an O-ring. The moisture sensor 9 is a resistance monitoring sensor. The sensing head of the moisture sensor 9 consists of two wires 901. A warning sealing cavity 16 is formed between the inner side wall of the first layer hole 204 of the positioning ring 2, the outer circular surface of the roller 1, the inner seal 3, and the middle seal 4. The sensing head extends into the warning sealing cavity 16. The resistance value of the moisture sensor 9 inside the warning sealing cavity 16 is monitored in real time as an early warning indicator of seal failure. When the warning sealing cavity 16 is dry and free of moisture intrusion, the normal operating resistance value of the moisture sensor 9 is RΩ. However, when moisture is present in the warning sealing cavity 16, the two wires 901 of the moisture sensor 9 are connected, and its resistance decreases sharply and instantaneously. When it drops below 0.1RΩ, it indicates that the outer seal 5 and the middle seal 4 have failed. The dry granulation machine control system will issue an early warning, control the equipment to stop running, and promptly replace the outer seal 5 and the middle seal 4.

[0035] As a preferred option, such as Figure 2 As shown, the central sealing opening includes a first vertical sealing lip 4032, a second vertical sealing lip 4033, and a horizontal sealing lip 4034. The first vertical sealing lip 4032 and the second vertical sealing lip 4033 are respectively opened on the vertical inner surface of the labyrinth-type sealing body 403 in an upper and lower position. The first vertical sealing lip 4032 and the second vertical sealing lip 4033 are interference-fitted with the inner side of the vertical side of the inner skeleton 402. The right end of the inner diameter of the labyrinth-type sealing body 403 is provided with a horizontal sealing lip 4034 facing the right side, which is interference-fitted with the outer diameter of the lower bent side of the inner skeleton 402.

[0036] As a preferred option, such as Figure 2 As shown, the labyrinth-type sealing body 403 is also provided with a cup-shaped lip 4031, which is located above the first vertical sealing lip 4032 on the same side, forming a non-contact seal with the bent edge on the inner skeleton 402.

[0037] Preferably, grease is applied to the cavities formed by the mating surfaces of the outer sealing lip 501, the inner sealing left lip 3011, the inner sealing right lip 3012 and the roller 1 to form a grease diaphragm, which is used to alleviate frictional wear between the outer sealing lip 501, the inner sealing left lip 3011, the inner sealing right lip 3012 and the roller 1; grease is also applied to the cavities formed by the mating surfaces of the first vertical sealing lip 4032, the second vertical sealing lip 4033, the horizontal sealing lip 4034 and the inner skeleton 402 to form a grease diaphragm, which is used to alleviate frictional wear between the first vertical sealing lip 4032, the second vertical sealing lip 4033, the horizontal sealing lip 4034 and the inner skeleton 402.

[0038] Preferably, the axial distance L1 between the cavity formed by the outer seal 5 and the middle seal 4 is set to 15 mm, and the axial distance L2 between the cavity formed by the middle seal and the inner seal is set to 40 mm.

[0039] L1 and L2 need to be long enough. The longer these two values ​​are, the longer the path of powder invasion and the more significant the maze effect.

[0040] Preferably, the right end face of the first flange 201 of the positioning ring 2 is provided with an annular sealing groove 207, and an O-ring 17 is provided in the annular sealing groove 207. The right end face of the first flange 201 is sealed and fitted with the left end face of the bearing seat 11, and is fixedly connected by multiple locking bolts.

[0041] Preferably, a sealing ring 8 and a pressure ring 14 are provided between the right end face of the pressure cap 7 and the left side face of the roller pressing box 10 and the left end face of the positioning ring 2. The sealing ring 8 is sleeved on the roller shaft 1. A gap is left between the inner circular surface of the roller shaft through hole of the box panel 1001 and the outer circular surface of the positioning ring 2. A right-protruding annular n-shaped sealing ring is provided in the middle of the sealing ring 8. The annular n-shaped sealing ring is inserted into the gap. The right end face of the outer ring of the sealing ring 8 is in contact with the left side face of the box panel 1001, and the right end face of the inner ring is in contact with the left end face of the positioning ring 2. The pressure ring 14 is sleeved on the roller shaft 1. On shaft 1, the right end face is in contact with the left end face of the outer ring of sealing ring 8, and the pressure ring 14 and sealing ring 8 are fixedly connected to the housing panel 1001 by several second clamping screws. The right end face of the pressure cover 7 is in contact with the left end face of the inner ring of sealing ring 8, and is fixedly connected to sealing ring 8 and positioning ring 2 by several first clamping screws. The outer circular surface of the left end of the pressure cover 7 is provided with an outwardly extending second flange 703. An elastic sliding pad 13 is fixedly connected to the right end face of the second flange 703, and the right end face of the elastic sliding pad 13 is in contact with the left end face of the pressure ring 14.

[0042] like Figure 6 As shown, the working method of this embodiment is as follows: When the dry granulator is working, the roller 1 will rotate. In the roller pressing working area 6 inside the roller pressing box, the rotating roller 1 performs roller pressing work on the powder raw material. There are a large amount of randomly distributed dust 18 in the roller pressing working area 6. The powder will accumulate at the outer sealing lip 501. With the rotation of the roller 1, the outer sealing lip 501 will wear. After a time t1 = 250h, when the wear at this point causes the interference between the outer sealing lip 501 and the roller 1 to be completely lost, the dust 18 will invade into the cavity formed by the outer seal 5 and the middle seal 4 along the gap.

[0043] After time t2 = 120 hours, the dust crosses the path L1 = 15 mm and further enters the bend in the inner skeleton 402. The cup-shaped lip 4031 reaches its limit in accommodating the intruding dust 18. After time t3 = 210 hours, it will move along... Figure 6The center arrow penetrates the interference fit area between the first vertical sealing lip 4032 and the inner skeleton 402, where frictional wear occurs. After time t4 = 330 hours, the interference fit between the first vertical sealing lip 4032 and the inner skeleton 402 is completely lost; further along... Figure 6 The center arrow penetrates the interference fit area between the second vertical sealing lip 4033 and the inner skeleton 402, where frictional wear occurs. After time t5 = 350 hours, the interference fit between the second vertical sealing lip 4033 and the inner skeleton 402 is completely worn away. Further along... Figure 6 The center arrow penetrates the interference fit area between the horizontal sealing lip 4034 and the inner skeleton 402, where friction and wear occur. After a time of t6 = 160h, the interference fit between the horizontal sealing lip 4034 and the inner skeleton 402 is completely worn away.

[0044] By this point, after a cumulative total of t1+t2+t3+t4+t5+t6=1420h, the interference fit of the sealing lips of the outer sealing lip 501, the first vertical sealing lip 4032, the second vertical sealing lip 4033, and the horizontal sealing lip 4034 on the outer seal 5 and the middle seal 4 has been completely worn away. During this period, a total of 120 batches of dry granulation particles were produced, and the roller pressing working area 6 was cleaned 60 times.

[0045] Therefore, it can be seen that the labyrinth seal of the present invention has a working time of up to 1420 hours, while the working time of the existing single sealing lip is only 300 hours. The working time of the 7 sets of sealing lips in the present invention is 4.7 times that of the existing single sealing lip, which greatly improves the reliability of the seal, extends the service life of the sealing structure of the roller pressing mechanism of the dry granulator, and can effectively prevent the dust 18 of the powder raw material from contaminating the drive mechanism for a long time. At the same time, it blocks the communication between the external environment and the dust 18 in the granulation space, prevents the dust 18 from contaminating the external environment, and controls the contamination of the dust 18 by external microorganisms, thereby ensuring the quality of the granulated product.

[0046] like Figure 6 As shown, Embodiment 2 of the present invention: The method for early warning of sealing failure of the labyrinth seal of the dry granulator roller pressing mechanism in Embodiment 1 above includes the following steps:

[0047] S1. Seal Failure Warning: During normal operation, the resistance of moisture sensor 9 is RΩ. The lower warning limit resistance is set to 0.1RΩ in the granulator control system. The dry granulator's operation involves rolling powder into sheets. Processing is done in batches. Operators need to periodically clean the powder inside the roller press chamber 10 and then rinse it with clean water. Especially when the powder composition differs between the previous and next batches, the roller press chamber needs to be cleaned after each batch is processed. This cleaning process is necessary as the dry granulator's operating time increases. The outer sealing lip, the first vertical sealing lip, the second vertical sealing lip, and the horizontal sealing lip will gradually wear down. Due to the loss of interference due to wear, the seal will fail. When cleaning the roller press box, moisture and dust will enter the sealed cavity formed by each sealing lip from the outside to the inside as each sealing lip fails, until it enters the warning sealing cavity 16. When the moisture sensor 9 senses that its resistance drops sharply and instantly, it indicates that the outer seal 5 and the middle seal 4 have failed. The dry granulator control system will issue a warning and control the equipment to stop running.

[0048] like Figure 7 The figure shown is a resistance monitoring curve of the moisture sensor 9 in Embodiment 2 of the present invention;

[0049] S2. Handling of seal failure: Disassemble and inspect the labyrinth seal structure. Use a microscope to observe the wear of the outer sealing lip 501, the first vertical sealing lip 4032, the second vertical sealing lip 4033, the horizontal sealing lip 4034, the inner left sealing lip 3011, and the inner right sealing lip 3012. Use a dimensional measuring instrument to check the interference δ between the outer sealing lip 501, the first vertical sealing lip 4032, the second vertical sealing lip 4033, the horizontal sealing lip 4034, the inner left sealing lip 3011, and the inner right sealing lip 3012 and their corresponding mating surfaces. Replace the outer seal 5 and the middle seal 4 in a timely manner.

[0050] Specific testing and handling procedures in Example 2: After 1420 hours, the outer seal 5 and middle seal 4 failed. The outer seal 5, middle seal 4, and inner seal 3 were disassembled, and the wear of the sealing lips was observed using a microscope. The wear of the lips of the outer seal 5 and middle seal 4 was very severe, while the wear of the lip of the inner seal 3 was relatively slight. The interference fit δ between each sealing lip and its corresponding mating surface was measured using a dimensional measuring instrument to further confirm the failure. The results of the interference fit comparison are shown in Table 2.

[0051] Table 2 Comparison of excess amount at each lip / lip opening

[0052]

[0053]

[0054] Based on the above failure warning and physical confirmation, the outer seal 5 and the middle seal 4 have completely failed and should be replaced immediately. They should also be assembled according to the assembly requirements in order to restore the operation of the dry granulation machine.

[0055] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A labyrinth seal for a dry granulation mill roller pressing mechanism, comprising a roller shaft, a bearing housing, and a roller pressing chamber, wherein the bearing housing is located at the right end of the roller shaft and has a supporting bearing inside; a first step is provided on the outer circumference of the roller shaft at a position corresponding to the supporting bearing; the inner ring of the supporting bearing is fastened to the outer circumference of the first step, and the outer ring is fastened to the inner circumference of the bearing housing; the other end of the roller shaft passes through the roller pressing chamber, characterized in that: The labyrinth seal is located between the roller press housing and the bearing housing on the roller shaft, and includes a positioning ring, an inner seal, a middle seal, a pressure cap, and an outer seal. The positioning ring is fitted between the bearing housing on the roller shaft and the right side panel of the roller press housing. A first flange extending outward is provided on the outer circumference of the right end. An outer stop is provided on the right end face of the first flange. The outer stop is inserted into the inner hole of the bearing housing and fits against the end face of the outer ring of the supporting bearing. The right end face of the first flange is sealed and fixedly connected to the left end face of the bearing housing. The positioning ring has a first through hole. A first countersunk hole is provided on the right side of the first through hole. A first layer of holes and a second layer of holes are provided sequentially on the left side. The diameter of the second layer of holes is larger than that of the first layer of holes. The outer circumference of the inner seal is interference-fitted into the first layer of holes. The outer surface of the inner seal is pressed against the right end face of the first layer hole and located at the right end of the positioning ring. The outer circle of the middle seal is interference-fitted into the second layer hole, and its right end face is pressed against the right end face of the second layer hole and located at the left end of the positioning ring. The positioning ring, inner seal, and middle seal form a whole component and are fitted onto the roller shaft. Both the inner seal and the middle seal are interference-fitted with the roller shaft. The left end of the positioning ring is inserted into the box panel, and its left end face is aligned with the left side of the box panel. The pressure cap has a second through hole, and a second countersunk hole is provided on the right side of the second through hole. The outer circle of the outer seal is interference-fitted into the second countersunk hole and forms a whole component with the pressure cap, which is fitted onto the roller shaft. The outer seal is interference-fitted with the roller shaft. The right end face of the pressure cap is sealed and fixedly connected to the left end face of the positioning ring and the left side of the box panel. The outer sealing lip is provided at the left end of the inner diameter of the outer seal and faces to the left. The outer sealing lip is interference-fitted with the outer surface of the roller. The roller shaft has a second step corresponding to the second layer hole for positioning the middle seal. The middle seal includes an inner skeleton, a labyrinth seal body, and an outer skeleton. The inner skeleton has two 90-degree rightward bends, one upper and one lower, which are parallel to the roller shaft. The inner diameter of the lower bend is interference-fitted with the outer circular surface of the second step of the roller shaft. The outer side of the inner skeleton has a layer of inner skeleton rubber coating, which extends and covers the junction between the inner skeleton and the roller shaft, forming a seal at that point. The labyrinth seal body is located between the inner skeleton and the outer skeleton and has multiple middle seal lips, which are interference-fitted with the inner side of the inner skeleton. The upper end of the outer skeleton has a 90-degree leftward bend, and the outer side of this bend has a layer of outer skeleton rubber coating, which covers the junction between the outer skeleton and the inner circular surface of the second layer hole, forming a seal at that point. The outer skeleton rubber coating and the labyrinth seal body are connected as an integral structure. The inner seal includes an inner seal skeleton and an inner seal body. The inner seal body has a left inner seal lip facing left at its left end and a right inner seal lip facing right at its right end. Both the left and right inner seal lips are interference-fitted with the corresponding outer circular surfaces of the roller shaft. The inner seal skeleton is located inside the inner seal body. The inner seal skeleton is covered with a skeleton rubber coating. The skeleton rubber coating covers the inner circumferential surface where the inner seal skeleton and the positioning ring connect, forming a seal on the inner circumferential surface at the connection. The skeleton rubber coating and the inner seal body are connected as an integral structure. A sealing ring and a pressure ring are provided between the right end face of the pressure cap and the left side face of the roller pressing box and the left end face of the positioning ring. The sealing ring is sleeved on the roller shaft. A gap is left between the inner circular surface of the roller shaft through hole of the box panel and the outer circular surface of the positioning ring. A right-protruding annular n-shaped sealing ring is provided in the middle of the sealing ring. The annular n-shaped sealing ring is inserted into the gap. The right end face of the outer ring of the sealing ring is in contact with the left side face of the box panel, and the right end face of the inner ring is in contact with the left end face of the positioning ring. The pressure ring is sleeved on the roller shaft, and its right end face is in contact with the left end face of the outer ring of the sealing ring. The pressure ring and the sealing ring are fixedly connected to the box panel by several second clamping screws. The right end face of the pressure cap is in contact with the left end face of the inner ring of the sealing ring, and is fixedly connected to the sealing ring and the positioning ring by several first clamping screws. A second flange extending outward is provided on the outer circular surface of the left end of the pressure cap. An elastic sliding pad is fixedly connected to the right end face of the second flange. The right end face of the elastic sliding pad is in contact with the left end face of the pressure ring. It also includes a moisture sensor. An early warning sealing cavity is formed between the inner wall of the first layer hole of the positioning ring, the outer circular surface of the roller, the inner seal, and the middle seal. The sensing head of the moisture sensor extends into the early warning sealing cavity.

2. The labyrinth seal of the roller pressing mechanism of a dry granulator according to claim 1, characterized in that: The outer wall of the positioning ring has a radially threaded hole in the middle, which communicates with the first layer hole. A moisture sensor is threaded into the threaded hole. The moisture sensor and the positioning ring are statically sealed by an O-ring. The moisture sensor is a resistance monitoring sensor. The sensing head of the moisture sensor consists of two wires, which monitor the resistance value of the moisture sensor in the warning sealing cavity in real time as an early warning indicator of seal failure. When the warning sealing cavity is dry and free of moisture intrusion, the normal operating resistance value of the moisture sensor is RΩ. When moisture is present in the warning sealing cavity, the two wires of the moisture sensor are connected, and its resistance drops sharply and instantaneously. When it drops below 0.1RΩ, it indicates that the outer seal and the middle seal have failed. The dry granulation machine control system will issue an early warning, stop the equipment, and replace the outer seal and the middle seal in time.

3. The labyrinth seal of the roller pressing mechanism of a dry granulator according to claim 2, characterized in that: The central sealing opening includes a first vertical sealing lip, a second vertical sealing lip, and a horizontal sealing lip. The first and second vertical sealing lips are respectively opened on the vertical inner surface of the labyrinth-type sealing body at the top and bottom. The first and second vertical sealing lips are interference-fitted with the inner side of the vertical side of the inner skeleton. The right end of the inner diameter of the labyrinth-type sealing body is provided with a horizontal sealing lip facing the right, which is interference-fitted with the outer diameter of the lower bent side of the inner skeleton.

4. The labyrinth seal of the roller pressing mechanism of a dry granulator according to claim 3, characterized in that: The labyrinth-type sealing body is also provided with a cup-shaped lip, which is located above the first vertical sealing lip on the same side, forming a non-contact seal with the bent edge on the inner skeleton.

5. The labyrinth seal of the roller pressing mechanism of a dry granulator according to claim 4, characterized in that: The cavities formed by the outer sealing lip, the left inner sealing lip, the right inner sealing lip, and the mating surfaces with the roller shaft are all coated with grease to form a grease diaphragm, which is used to alleviate frictional wear between the outer sealing lip, the left inner sealing lip, the right inner sealing lip, and the roller shaft; the cavities formed by the first vertical sealing lip, the second vertical sealing lip, the horizontal sealing lip, and the mating surfaces with the inner skeleton are all coated with grease to form a grease diaphragm, which is used to alleviate frictional wear between the first vertical sealing lip, the second vertical sealing lip, the horizontal sealing lip, and the inner skeleton.

6. The labyrinth seal of the roller pressing mechanism of a dry granulator according to claim 5, characterized in that: The axial distance L1 between the outer seal and the middle seal is set to 15-20 mm, and the axial distance L2 between the middle seal and the inner seal is set to 40-45 mm.

7. The labyrinth seal of the roller pressing mechanism of a dry granulator according to claim 1, characterized in that: The right end face of the first flange of the positioning ring is provided with an annular sealing groove, and an O-ring is provided in the annular sealing groove. The right end face of the first flange is sealed and fitted with the left end face of the bearing seat, and is fixedly connected by multiple locking bolts.

8. A method for early warning of seal failure of the labyrinth seal of the roller pressing mechanism of a dry granulator as described in any one of claims 1 to 7, characterized in that... Includes the following steps: S1. Seal Failure Warning: During normal operation, the resistance of the moisture sensor is RΩ. The lower limit resistance of the warning is set to 0.1RΩ in the control system of the granulator. The working process of the dry granulator is to roll the powder into sheets. The work is done in batches. The operator needs to clean the powder inside the roller press box regularly and then wash it with clean water. When the powder composition of the previous batch is different from that of the next batch, the roller press box needs to be cleaned after the previous batch is completed. As the dry granulator works for a long time, the outer sealing lip, the first vertical sealing lip, the second vertical sealing lip, and the horizontal sealing lip will gradually wear down. Due to the loss of interference fit due to wear, the seal fails. When cleaning the roller press box, moisture and dust will enter the sealed cavity formed by each sealing lip from the outside to the inside as each sealing lip fails, until it enters the warning sealing cavity. This causes the moisture sensor to sense that its resistance drops sharply and instantly. When it is below 0.1RΩ, it indicates that the outer seal and the middle seal have failed. The dry granulator control system will issue a warning and control the equipment to stop running. S2. Handling of seal failure: Disassemble and inspect the labyrinth seal structure. Use a microscope to observe the wear of the outer sealing lip, the first vertical sealing lip, the second vertical sealing lip, the horizontal sealing lip, the left inner sealing lip, and the right inner sealing lip. Use a dimensional measuring instrument to check the interference δ between the outer sealing lip, the first vertical sealing lip, the second vertical sealing lip, the horizontal sealing lip, the left inner sealing lip, and the right inner sealing lip and their corresponding mating surfaces. Replace the outer seal and the middle seal in a timely manner.

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