Dry granulator roller mechanism, sealing structure thereof and sealing failure early warning method

Abstract

The application discloses a dry granulator roller pressing mechanism and a sealing structure and a sealing failure early warning method thereof. The sealing structure is arranged between a roller pressing box and a bearing seat on a 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 provided in an interference fit in a stepped hole of the positioning ring and are both in interference fit with the roller shaft. The outer seal is provided in an interference fit in a third hole of the gland and is in interference fit with the roller shaft. A first lip is arranged on a left end of the outer seal, a second lip is arranged on a left end in the middle seal, a third lip is arranged in the middle, a fourth lip is arranged on a left end in the inner seal, and a fifth lip is arranged on a right end. The application adopts three seals of the inner seal, the middle seal and the outer seal, and five groups of lip-shaped seals, improves the sealing effect, improves the reliability of the seal, effectively prevents contamination of raw material powder on a driving mechanism and contamination of the external environment in a powder raw material tablet pressing and granulating process, prevents contamination of the external microorganisms on the powder raw material, and ensures the quality of the granulated product.

Description

Technical Field

[0001] This invention relates to the field of dry granulation machine technology, and in particular to a dry granulation machine roller pressing mechanism, its sealing structure, and a sealing failure early warning method. 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 the external environment, and cause cross-contamination by microorganisms, thus affecting product quality, this invention provides a roller pressing mechanism for a dry granulation machine, its sealing structure, and a sealing failure early warning method. Sealing structures are installed on the left and right sides of the roller pressing box on both the driving and driven roller shafts. Each sealing structure employs five sets of lip dynamic seals (internal, middle, and external seals), and uses an air-pressure chamber for inflation. A pressure sensor provides real-time monitoring and early warning, allowing for immediate detection of seal failure, immediate equipment shutdown, and timely replacement, thus solving the aforementioned technical problems.

[0004] To achieve the above objectives, the present invention provides a sealing structure for a 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 has a supporting bearing inside. The inner ring of the supporting bearing is fastened to the outer circular surface of the roller shaft, and the outer ring is fastened to the inner circular surface of the bearing housing. The other end of the roller shaft passes through the roller pressing box. The sealing structure is located on the roller shaft between the roller pressing box and the bearing housing, 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 and the box panel on the roller shaft. A first flange extending outward is provided on the outer circular surface of the right end. An outer stop is provided on the right end face of the first flange, which is inserted into the inner hole of the bearing housing. 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 second through hole, and a third through hole with increasing diameter from right to left. The device comprises a first-layer hole and a second-layer hole. The inner seal is fitted with an interference fit around the outer circle of the first-layer hole, with its right end face pressed against 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 around the outer circle of the second-layer hole, with its right end face pressed against 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 together form a single component fitted onto the roller shaft. Both the inner and middle seals are interference-fitted with the roller shaft. The left end of the positioning ring is inserted into the housing panel, with its left end face aligned with the left side of the housing panel. The pressure cap has a second through hole, and a third-layer hole is located to the right of the second through hole. The outer seal is fitted with an interference fit around the outer circle of the third-layer hole, forming a single component 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 / or the left side of the housing panel. The outer seal has a first lip facing left at the upper left end of its inner side surface, and the first lip is interference-fitted with the outer circular surface of the roller shaft; the middle seal has a second lip facing left at the upper left end of its inner side surface, and a third lip facing left at the middle of its inner side surface, and both the second and third lips are interference-fitted with the outer circular surface of the roller shaft; the inner seal is a right-frame-shaped sealing ring with an opening on the left side, and the inner seal has a fourth lip facing right at the upper left end of its inner side surface, and a fifth lip facing right at the upper right end of its inner side surface. The outer wall of the positioning ring has a radially threaded hole in the middle, which communicates with the first layer hole. An air sleeve is threaded into the first threaded hole. The air sleeve and the positioning ring are statically sealed by an O-ring. An air pipe is sealed to the upper end of the air sleeve. The other end of the air pipe is connected to an external air compressor. A pressure sensor is provided on the air pipe to deliver compressed air into the first layer hole through the air pipe, so that a pressure cavity is formed between the inner wall of the first layer hole, the outer surface of the driven roller shaft, the inner seal, and the outer seal. The pressure sensor monitors the pressure in the pressure cavity as an early warning indicator of seal failure.

[0005] As a further improvement to this technology, grease is applied to the cavity formed by the first lip, second lip, third lip, fourth lip, and fifth lip and the mating surface of the roller shaft to alleviate friction and wear.

[0006] As a further improvement to this technology, a first annular sealing groove is provided on the right end face of the first flange of the positioning ring, and a first O-ring is provided in the first 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.

[0007] As a further improvement to this technology, a second annular sealing groove is provided on the right end face of the cover, and a second O-ring is provided in the second annular sealing groove. The right end face of the cover is sealed and fitted with the left end face of the positioning ring, and the cover and the positioning ring are fixedly connected by a number of first clamping screws.

[0008] 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 first 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 first 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.

[0009] The present invention also provides a dry granulation roller pressing mechanism, characterized in that: the roller pressing mechanism includes a frame, an active roller pressing assembly and a driven roller pressing assembly; The active roller pressing assembly is located at the lower part of the frame and includes a reducer, an active roller shaft, an active gear, a first support bearing, and an active pressure roller. The reducer is located on the right side of the roller pressing housing. The right end of the active roller shaft is fixedly connected to the output shaft of the reducer, and the other end passes through the roller pressing housing. There are two first support bearings, and the inner rings of the two first support bearings are respectively fastened to the outer circles of both ends of the active roller shaft to support the active roller shaft. The first support bearing is located in the lower bearing seat, which is fixedly installed on the frame. The active gear is installed at the right end of the active roller shaft, located to the right of the lower bearing seat. The active pressure roller is located in the roller pressing housing and is sleeved in the middle of the active roller shaft. The roller pressing housing is fixedly connected to the frame. A set of the above-mentioned sealing structure is installed between the left and right sides of the roller pressing housing on the active roller shaft and the corresponding lower bearing seats. The driven roller assembly is located on the upper part of the support and includes a driven roller shaft, a driven gear, a second support bearing, and a driven pressure roller. The driven roller shaft is parallel to the driving roller shaft. The driven gear is installed at the right end of the driven roller shaft and meshes with the driving gear. There are two second support bearings, and the inner rings of the two second support bearings are respectively fastened to the outer circles of both ends of the driven roller shaft to support the driven roller shaft. The second support bearing is located in the upper bearing seat. The upper bearing seat is installed on the hydraulic floating device on the support, so that the driven roller assembly can float up and down with the hydraulic floating device. The position of the upper bearing seat is aligned with the lower bearing seat. The driven pressure roller is sleeved in the middle of the driven roller shaft and corresponds to the position of the driving pressure roller. A set of the above-mentioned sealing structure is installed between the left and right sides of the roller pressing box on the driven roller shaft and the corresponding upper bearing seat. The active pressure roller and the driven pressure roller are provided with a second gap in the radial direction. The size of the second gap can be adjusted by adjusting the pressure of the hydraulic floating device. It is used to roll products of different thicknesses. The sealing ring and elastic sliding pad of the sealing structure form a sliding sealing structure when the hydraulic floating device is adjusted.

[0010] As a further improvement to this technology, a pneumatic cavity is formed between the third lip, the fourth lip, the positioning ring, and the driving or driven roller shaft of the sealing structure. The calibrated gas pressure P0 of the gas filling the pneumatic cavity is set to 40% to 80% of the maximum pressure resistance of the cavity.

[0011] The present invention also provides a method for early warning of sealing failure of the sealing structure of the roller pressing mechanism of the above-mentioned dry granulator, characterized by comprising the following steps: S1. Working air pressure calibration: Cut off the second lip on the left side of the middle seal, apply soapy water around the roller shaft near the left side of the third lip, and gradually inflate the air chamber through an external air compressor via the air pressure sensor, air pipe, air jacket, and positioning ring. When the soapy water applied on the left side bubbles, it indicates that a leak has occurred at the third lip. Record the air pressure sensor value at this time. This value is the maximum pressure resistance value Pmax of the air chamber; working air pressure Po = 40%~80% Pmax; It should be noted that: because the inner seal is a frame-shaped sealing ring with the opening facing into the air pressure chamber, the fourth lip will be pressed tightly against the roller shaft under the pressure of inflation, while the third lip will be detached from the roller shaft under the pressure of inflation. Therefore, as air is gradually inflated into the air pressure chamber, the third lip will open first. S2, Seal Failure Warning: The upper warning pressure Pu=1.1Po and the lower warning pressure Pd=0.9Po are set in the control system of the granulator. When the pressure inside the air chamber drops sharply and exceeds the lower limit of Pd, the control system of the granulator stops working, indicating that the first lip, the second lip and the third lip have all worn and failed, and lost the interference fit. S3. Handling of seal failure: Disassemble the seal structure for inspection. Use an optical microscope or tool microscope to observe the wear of the first lip, second lip, and third lip. Use a dimensional measuring instrument to measure the inner diameter of the first lip, second lip, and third lip. The measured inner diameter value is di. At this time, the driving roller or driven roller will also have corresponding slight wear. The corresponding measured outer diameter value of the driving roller or driven roller is do. Therefore, the interference of each lip after operation is obtained as: δ=(do-di) / 2. If the interference fit δ of each lip is less than 0, it can be determined that the outer seal and the middle seal need to be replaced; if the interference fit δ of each lip is greater than or equal to 0, check the external air compressor to ensure that the pressure is not too high.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The sealing structure of this invention adopts three seals: inner, middle, and outer, with a total of 5 sets of dynamic lip seals. O-ring seals are used between the connecting surface of the positioning ring and the bearing seat, and between the connecting surface of the pressure cap and the positioning ring. A sealing ring is used between the roller pressing box 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 sealing structure. 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.

[0013] 2. This invention is equipped with a seal failure early warning device. First, the equipment control system sets the upper and lower limit air pressure values ​​of the air pressure chamber. By inflating the air pressure chamber, the air pressure inside the chamber is monitored in real time using an air pressure sensor. When the air pressure inside the chamber suddenly drops sharply and exceeds the lower limit value, it indicates that the first, second, and third lips have all worn out and lost their interference fit, resulting in seal failure. The control system can know the seal failure situation immediately and control the equipment to stop operating immediately, allowing the staff to deal with it in time and replace the worn seals that have failed. This prevents damage caused by the equipment continuing to operate under seal failure conditions, extends the service life of the equipment, and saves equipment maintenance costs.

[0014] 3. The driven roller assembly of the present invention is fixed to the frame by a hydraulic floating device. To prevent dust leakage, it is connected to the housing panel in the middle by a sealing ring and a sliding pad. The housing panel is also fixedly connected to the frame. When the driven roller assembly floats radially up and down due to the roller force, the sealing ring and sliding pad in the middle are flexibly connected, which can meet the sealing requirements of the driven mechanism under sliding working conditions, thereby preventing dust leakage. Attached Figure Description

[0015] Figure 1 for Figure 3 Enlarged schematic diagram of the sealing structure of the floating driven roller assembly at point I; Figure 2 for Figure 3 Enlarged structural diagram of section II (active roller pressing assembly sealing structure); Figure 3 This is a schematic diagram of the roller pressing mechanism of the dry granulation machine according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the internal left cross-sectional structure of the roller pressing box according to an embodiment of the present invention; Figure 5 for Figure 3 Enlarged structural diagram of section III (the gap between the driving and driven pressure rollers); Figure 6 This is a schematic diagram of the positioning ring structure according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the pressure cap structure in Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the pressure cap structure in Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the five sets of lip structures and sealing principle on the inner, middle and outer seals of an embodiment of the present invention; Figure 10 This is a schematic diagram illustrating the working pressure calibration principle of the pneumatic chamber according to an embodiment of the present invention; Figure 11This is a diagram showing the internal air pressure of the air pressure chamber in the sealed structure of the driven roller assembly according to an embodiment of the present invention.

[0016] In the diagram: 1. Gearbox, 2. Driven roller shaft, 3. Driven gear, 4. Lower bearing housing, 5. Driven pressure roller, 6. Support bracket, 7. First support bearing, 8. Driven roller shaft, 9. Driven gear, 10. Upper bearing housing, 11. Driven pressure roller, 12. Second support bearing, 13A. Sealing structure, 13B. Sealing structure, 131. Positioning ring, 1311. First flange, 1312. Outer stop, 1313. First through hole, 1314. First layer hole, 1315. Second layer hole, 1316. First threaded hole, 1317. First annular sealing groove, 132. Inner seal, 1321. Fourth lip, 1322. Fifth lip, 133. Middle seal, 1331. Second lip. 1332. Third lip; 134A. Gland; 134B. Gland; 1341. Second through hole; 1342. Third layer hole; 1343. Second flange; 1344. Second annular sealing groove; 135. Outer seal; 1351. First lip; 136. Sealing ring; 1361. N-ring seal; 137. Pressure ring; 138. Elastic sliding pad; 139. First O-ring seal; 14. Roller press box; 141. Box panel; 1411. First gap; 15. Air jacket; 16. Air pipe; 17. Air pressure sensor; 18. Powder raw material; 19. Press; 20. Second O-ring seal; 21. Air pressure chamber; 22. Lubricating grease; 23. Second gap; 24. Dust. Implementation

[0017] 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.

[0018] like Figure 1 , 6As shown in Figures 7 and 9, Embodiment 1 of the present invention: The sealing structure 13A of the roller pressing mechanism includes a driven roller shaft 8, an upper bearing seat 10, and a roller pressing box 14. The upper bearing seat 10 is located at the right end of the driven roller shaft 8, and a second support bearing 12 is provided inside it. The inner ring of the second support bearing 12 is fastened to the outer circular surface of the driven roller shaft 8, and the outer ring is fastened to the inner circular surface of the upper bearing seat 10. The other end of the driven roller shaft 8 passes through the roller pressing box 14. The sealing structure 13A is located between the driven roller shaft 8, the roller pressing box 14, and the upper bearing seat 10, and includes a positioning ring 131, an inner ring 132, and an inner bearing seat 14. The system comprises a seal 132, a middle seal 133, a gland 134A, and an outer seal 135. A positioning ring 131 is fitted between the upper bearing seat 10 and the housing panel 141 on the driven roller shaft 8. A first flange 1311 extending outward is provided on the outer circumference of the right end. An outer stop 1312 is provided on the right end face of the first flange 1311. The outer stop 1312 is inserted into the inner hole of the upper bearing seat 10, and its end face abuts against the end face of the outer ring of the second support bearing 12. The right end face of the first flange 1311 is sealed and fixedly connected to the left end face of the upper bearing seat 10. The positioning ring 131... The inner ring 1311 has a first through hole 1313, a first layer hole 1314, and a second layer hole 1315 with the diameter increasing from right to left. The outer circle of the inner seal 132 is interference-fitted into the first layer hole 1314, with its right end face close to the right end face of the first layer hole 1314, located at the right end of the positioning ring 131. The outer circle of the middle seal 133 is interference-fitted into the second layer hole 1315, with its right end face close to the right end face of the second layer hole 1315, located at the left end of the positioning ring 131. The positioning ring 131, the inner seal 132, and the middle seal 133 constitute a complete component. Located on the driven roller shaft 8, the inner seal 132 and the middle seal 133 are both interference-fitted with the driven roller shaft 8. The left end of the positioning ring 131 is inserted into the box panel 141, and the left end face is aligned with the left side face of the box panel 141. The pressure cover 134A has a second through hole 1341, and a third layer hole 1342 is provided on the right side of the second through hole 1341. The outer circle of the outer seal 135 is interference-fitted into the third layer hole 1342, and together with the pressure cover 134A, they form a component and are integrally fitted onto the driven roller shaft 8. The outer seal 135 is interference-fitted with the driven roller shaft 8. A sealing ring 136 and a pressure ring 137 are provided between the right end face of the pressure cap 134A and the left side face of the roller pressing box 14 and the left end face of the positioning ring 131. The sealing ring 136 is sleeved on the driven roller shaft 8. A first gap 1411 is left between the inner circular surface of the roller shaft through hole of the box panel 141 and the outer circular surface of the positioning ring 131. A right-protruding annular n-shaped sealing ring 1361 is provided in the middle of the sealing ring 136. The annular n-shaped sealing ring 1361 is inserted into the first gap 1411. The right end face of the outer ring of the sealing ring 136 is in contact with the left side face of the box panel 141, and the right end face of the inner ring is in contact with the left end face of the positioning ring 131. The pressure ring 137... The pressure ring 137 is fitted onto the driven roller shaft 8, with its right end face fitting against the left end face of the outer ring of the sealing ring 136. The pressure ring 137 and the sealing ring 136 are fixedly connected to the housing panel 141 by several second clamping screws. The right end face of the pressure cover 134A is fitted against the left end face of the inner ring of the sealing ring 136, and is fixedly connected to the sealing ring 136 and the positioning ring 131 by several first clamping screws. The outer circular surface of the left end of the pressure cover 134A is provided with an outwardly extending second flange 1343. An elastic sliding pad 138 is fixedly connected to the right end face of the second flange 1343, and the right end face of the elastic sliding pad 138 is fitted against the left end face of the pressure ring 137.

[0019] The outer seal 135 has a first lip 1351 facing left at the left end of the inner side, and the first lip 1351 is interference-fitted with the outer circular surface of the driven roller shaft 8; the middle seal 133 has a second lip 1331 facing left at the left end of the inner side, and a third lip 1332 facing left at the middle of the inner side, and both the second lip 1331 and the third lip 1332 are interference-fitted with the outer circular surface of the driven roller shaft 8; the inner seal 132 is a right frame-shaped sealing ring with an opening on the left side, and the inner seal 132 has a fourth lip 1321 facing right at the left end of the inner side, and a fifth lip 1322 facing right at the right end; The outer wall of the positioning ring 131 has a radially threaded hole 1316 at its center. The first threaded hole 1316 communicates with the first layer hole 1314. An air sleeve 15 is threadedly connected to the first threaded hole 1316. The air sleeve 15 and the positioning ring 131 are statically sealed by an O-ring. An air pipe 16 is sealed to the upper end of the air sleeve 15. The other end of the air pipe 16 is connected to an external air compressor. A pressure sensor 17 is provided on the air pipe 16 to deliver compressed air into the first layer hole 1314 through the air pipe 16, so that a pressure cavity 21 is formed between the inner wall of the first layer hole 1314, the outer surface of the driven roller shaft 8, the inner seal 132, and the outer seal 133. The pressure sensor 17 monitors the pressure in the pressure cavity 21 as an early warning indicator of seal failure.

[0020] Lubricating grease 22 is applied to the cavity formed by the mating surfaces of the first lip 1351, the second lip 1331, the third lip 1332, the fourth lip 1321, and the fifth lip 1322 with the driven roller shaft 8 to alleviate friction and wear.

[0021] The first flange 1311 of the positioning ring 131 has a first annular sealing groove 1312 on its right end face, and a first O-ring 139 is provided in the first annular sealing groove 1312. The right end face of the first flange 1311 is sealed and fitted with the left end face of the upper bearing seat 10, and is fixedly connected by multiple locking bolts.

[0022] like Figure 4 , 8 As shown, in Embodiment 2 of the present invention, the sealing structure 13B of the roller pressing mechanism is basically the same as the sealing structure 13A of the roller pressing mechanism in Embodiment 1, except that: The right end face of the pressure cap 134B is provided with a second annular sealing groove 1344, and a second O-ring 20 is provided in the second annular sealing groove 1344. The right end face of the pressure cap 134B is sealed and fitted with the left end face of the positioning ring 131, and the pressure cap 134B and the positioning ring 131 are fixedly connected by a number of first clamping screws.

[0023] like Figure 1 , 2 As shown in Figures 3 and 4, Embodiment 3 of the present invention: The dry granulation roller pressing mechanism includes a frame 6, an active roller pressing assembly, and a driven roller pressing assembly; The active roller pressing assembly is located at the lower part of the frame 6 and includes a reducer 1, an active roller shaft 2, an active gear 3, a first support bearing 7, and an active pressure roller 5. The reducer 1 is located on the right side of the roller pressing box 14. The right end of the active roller shaft 2 is fixedly connected to the output shaft of the reducer 1, and the other end passes through the roller pressing box 14. There are two first support bearings 7. The inner rings of the two first support bearings 7 are respectively fastened to the outer circles of both ends of the active roller shaft 2 to support the active roller shaft 2. The first support bearing 7 is located in the lower bearing seat 4, which is fixedly installed on the frame 6. The active gear 3 is installed on the right end of the active roller shaft 2 by a flat key or spline, located on the right side of the lower bearing seat 4. The active pressure roller 5 is located in the roller pressing box 14 and is sleeved in the middle of the active roller shaft 2. The roller pressing box 14 is fixedly connected to the frame 6. A sealing structure 13B of the second embodiment of the present invention is installed between the left and right sides of the roller pressing box 14 on the active roller shaft 2 and the corresponding lower bearing seat 4. The driven roller assembly is located on the upper part of the bracket 6 and includes a driven roller shaft 8, a driven gear 9, a second support bearing 12, and a driven pressure roller 11. The driven roller shaft 8 is parallel to the driving roller shaft 2. The driven gear 9 is installed on the right end of the driven roller shaft 8 by a flat key or spline and meshes with the driving gear 3. There are two second support bearings 12. The inner rings of the two second support bearings 12 are respectively fastened to the outer circles of both ends of the driven roller shaft 8 to support the driven roller shaft 8. The second support bearings 12 are located in the upper bearing seat 10. The upper bearing seat 10 is installed on the hydraulic floating device (not shown in the figure) provided on the bracket so that the driven roller assembly can float up and down with the hydraulic floating device. The position of the upper bearing seat 10 is aligned with the lower bearing seat 4. The driven pressure roller 11 is sleeved in the middle of the driven roller shaft 8 and corresponds to the position of the driving pressure roller 5. A sealing structure 13A of the present invention is installed between the left and right sides of the roller pressing box 14 on the driven roller shaft 8 and the corresponding upper bearing seat 10. like Figure 5 As shown, the active pressure roller 5 and the driven pressure roller 11 are provided with a second gap 23 in the radial direction. The size of the second gap 23 can be adjusted by adjusting the pressure of the hydraulic floating device. It is used to roll products of different thicknesses. The sealing ring 136 and the elastic sliding pad 138 of the sealing structure 13A form a sliding sealing structure when the hydraulic floating device is adjusted.

[0024] like Figure 4 , 5 As shown, the powder raw material 18 in the roller press box 14 enters from the front side of the second gap 23 between the active pressure roller 5 and the driven pressure roller 11. After being rolled, it comes out from the rear side to become a pressing sheet 19 with the same thickness and width as the second gap 23.

[0025] like Figure 9 As shown, a pneumatic cavity 21 is formed between the third lip 1332, the fourth lip 1321, the positioning ring 131 of the sealing structures 13A and 13B and the driving roller 2 or the driven roller 8. The calibrated gas pressure P0 of the gas filling the pneumatic cavity 21 is set to 40% to 80% of the maximum pressure Pmax of the cavity.

[0026] like Figure 10 As shown in Embodiment 4 of the present invention: the sealing failure early warning method for the sealing structure of the dry granulator roller pressing mechanism in the above embodiments includes the following steps: S1. Working air pressure calibration: Cut off the second lip 1331 on the left side of the central seal 133. Apply soapy water around the roller shaft near the left side of the third lip 1332. Gradually inflate the air pressure chamber 21 through an external air compressor via the air pressure sensor 17, air pipe 16, air sleeve 15, and positioning ring 131. When the soapy water applied on the left side bubbles, it indicates that the third lip 1332 is leaking. Record the value of the air pressure sensor 17 at this time. This value is the maximum pressure resistance value Pmax of the air pressure chamber 21. Working air pressure Po = 40%~80% Pmax; It should be noted that: because the inner seal 132 is a frame-shaped sealing ring with its opening facing the inside of the air pressure chamber 21, the fourth lip 1321 will be pressed tightly against the roller shaft under the action of air pressure, while the third lip 1332 faces the outside of the air pressure chamber 21. Under the action of air pressure, the third lip 1332 will be disengaged from the roller shaft. Therefore, as air is gradually filled into the air pressure chamber, the third lip 1332 will open first. S2, Seal Failure Warning: The upper warning pressure Pu=1.1Po and the lower warning pressure Pd=0.9Po are set in the control system of the pellet mill, allowing for a pressure fluctuation of ±10% under dynamic operation. When the internal pressure of the air chamber 21 drops sharply and exceeds the lower limit Pd, the control system of the pellet mill stops the equipment, indicating that the first lip 1351, the second lip 1331, and the third lip 1332 have all worn out and lost their interference fit. S3. Handling of seal failure: Disassemble the seal structure for inspection. Use an optical microscope or tool microscope to observe the wear of the first lip 1351, the second lip 1331, and the third lip 1332. Use a dimensional measuring instrument to measure the inner diameter of the first lip 1351, the second lip 1331, and the third lip 1332. The measured inner diameter value is di. At this time, the driving roller 2 or the driven roller 8 will also have corresponding slight wear. The corresponding measured outer diameter value of the driving roller 2 or the driven roller 8 is do. Therefore, the interference of each lip after operation is obtained as: δ=(do-di) / 2. If the interference fit δ of each lip is less than 0, it can be determined that the outer seal 135 and the middle seal 133 need to be replaced; if the interference fit δ of each lip is greater than or equal to 0, check the external air compressor to ensure that the pressure is not too high.

[0027] like Figure 11 The figure shown is an internal air pressure curve of the air pressure chamber of the sealing structure 13A on one side of the driven roller assembly in Embodiment 3 of the present invention. The contact interference between the first lip 1351, second lip 1331, third lip 1332, fourth lip 1321, and fifth lip 1322 of the sealing structure and the driven roller shaft 8 is a=0.30mm, b=0.30mm, c=0.40mm, d=0.60mm, and e=0.20mm, respectively. The maximum pressure resistance value Pmax of the pneumatic chamber 21 is 0.2 MPa, and the internal inflation pressure Po=60%Pmax=0.12MPa. During operation, as the driven roller shaft 8 rotates, the inner seal 132, middle seal 133, and outer seal 135 are pressed onto the positioning ring 131 and the pressure cap 134A, respectively, and are fixedly connected to the hydraulic floating mechanism, without rotational movement. Therefore, the driven roller shaft 8 forms a sliding friction pair with the outer seal 1351, middle seal 133, and inner seal 132 through the grease diaphragm 22. As the driven roller shaft... As the driven roller 8 rotates, dust 24 formed from the dispersed powder raw material continuously invades the first lip 1351. The first lip 1351 wears down until it loses its interference fit. Further, dust 24 invades the second lip 1331, which also wears down with the rotation of the driven roller 8 until it loses its interference fit. Finally, dust 24 invades the third lip 1332, which also wears down with the rotation of the driven roller 8 until it loses its interference fit. At this point, the third lip 1332 will open, causing pressure relief inside the air pressure chamber 21. This is detected by the air pressure sensor 17, and the pressure relief curve it monitors is shown in the attached figure. Figure 11 As shown, from Figure 11 The monitoring curves show that after approximately 840 hours of cumulative operation, the air pressure chamber leaks, and the air pressure drops sharply. After a leak occurs, the control system stops the equipment. Workers promptly disassemble the sealing structure 13A and inspect the outer seal 135 and the middle seal 133. After disassembling these two parts, the inner diameters of the first lip 1351 on the outer seal 135 and the second lip 1331 and third lip 1332 on the middle seal 133 are measured using a dimensional measuring instrument: d1=50.22mm, d2=50.18mm, d3=49.98mm. The corresponding outer diameters of the driven roller shaft 8 at three locations are d1'=49.98mm, d2'=49.99mm, d3'=50.00mm. Therefore, the interference fits of the first lip 1351, second lip 1331, and third lip 1332 are as follows: δ1 = (d1' - d1) / 2 = -0.12 mm, indicating a clearance fit. δ2 = (d2' - d2) / 2 = -0.095mm, indicating a clearance fit. δ3 = (d3' - d3) / 2 = 0.01 mm, which is a small interference fit. Comparing the above interference with the initial interference a, b, and c, the interference lost due to wear can be determined as follows: f = a - δ1 = 0.30 + 0.12 = 0.42 mm g = b - δ² = 0.30 + 0.095 = 0.395 mm h = c - δ³ = 0.40 - 0.01 = 0.39 mm Through the above wear detection and analysis, it was found that the first lip 1351, the second lip 1331, and the third lip 1332 were all severely worn. The first lip 1351 and the second lip 1331 had lost their interference fit, while the third lip 1332 was also close to losing its interference fit.

[0028] Based on the above analysis, the outer seal 135 and the middle seal 132 need to be replaced in a timely manner.

[0029] 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 sealing structure for a roller pressing mechanism, comprising a roller shaft, a bearing housing, and a roller pressing box, wherein the bearing housing is located at the right end of the roller shaft and has a supporting bearing inside, the inner ring of the supporting bearing being fastened to the outer circular surface of the roller shaft, and the outer ring being fastened to the inner circular surface of the bearing housing, and the other end of the roller shaft passing through the roller pressing box, characterized in that: The sealing structure is located between the roller press housing and the bearing seat 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 seat and the housing panel on the roller shaft. 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, which is inserted into the inner hole of the bearing seat. The right end face of the first flange is sealed and fixedly connected to the left end face of the bearing seat. The positioning ring has a first through hole, a first layer hole, and a second layer hole with the diameter increasing sequentially from right to left. The outer circumference of the inner seal is interference-fitted into the first layer hole, and the right end face is close to the right end face of the first layer hole, located at the right end of the positioning ring. The middle seal... The outer circle of the seal is interference-fitted into the second layer hole, with its right end face pressed against 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 single component that is fitted onto the roller shaft. Both the inner and middle seals are interference-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 third layer hole is located to the right of the second through hole. The outer circle of the seal is interference-fitted into the third layer hole, forming a single component with the pressure cap that 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 seal has a first lip facing left at the upper left end of its inner side surface, and the first lip is interference-fitted with the outer circular surface of the roller shaft; the middle seal has a second lip facing left at the upper left end of its inner side surface, and a third lip facing left at the middle of its inner side surface, and both the second and third lips are interference-fitted with the outer circular surface of the roller shaft; the inner seal is a right-frame-shaped sealing ring with an opening on the left side, and the inner seal has a fourth lip facing right at the upper left end of its inner side surface, and a fifth lip facing right at the upper right end of its inner side surface. The outer wall of the positioning ring is provided with a radial first threaded hole in the middle, which communicates with the first layer hole. An air sleeve is threadedly connected to the first threaded hole. The air sleeve and the positioning ring are statically sealed by an O-ring. An air pipe is sealed to the upper end of the air sleeve. The other end of the air pipe is connected to an external air compressor. An air pressure sensor is provided on the air pipe to deliver compressed air into the first layer hole through the air pipe, so that an air pressure cavity is formed between the inner wall of the first layer hole, the outer surface of the driven roller shaft, the inner seal, and the middle seal. The air pressure sensor is used to monitor the air pressure in the air pressure cavity as an early warning indicator of seal failure. 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 first 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 first 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.

2. The sealing structure of the roller pressing mechanism according to claim 1, characterized in that: Lubricating grease is applied to the cavities formed by the first, second, third, fourth, and fifth lips and the mating surfaces of the roller shaft to alleviate friction and wear.

3. The sealing structure of the roller pressing mechanism according to claim 2, characterized in that: The first flange of the positioning ring has a first annular sealing groove on its right end face, and a first O-ring is provided in the first 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.

4. A roller pressing mechanism for a dry granulation machine, characterized in that: The roller pressing mechanism includes a frame, a driving roller pressing assembly, and a driven roller pressing assembly; The active roller pressing assembly is located at the lower part of the frame and includes a reducer, an active roller shaft, an active gear, a first support bearing, and an active pressure roller. The reducer is located on the right side of the roller pressing housing. The right end of the active roller shaft is fixedly connected to the output shaft of the reducer, and the other end passes through the roller pressing housing. There are two first support bearings, and the inner rings of the two first support bearings are respectively fastened to the outer circles of both ends of the active roller shaft to support the active roller shaft. The first support bearings are located in the lower bearing housing, which is fixedly installed on the frame. The active gear is installed on the right side of the active roller shaft. Located on the right side of the lower bearing seat at the right end, the active pressure roller is housed within the roller pressing box, fitted around the middle of the active roller shaft. The roller pressing box is fixedly connected to the frame. A sealing structure is installed between the left and right sides of the roller pressing box on the active roller shaft and the corresponding lower bearing seat. This sealing structure, located between the roller pressing box and the lower bearing seat on the active roller shaft, includes a positioning ring, an inner seal, a middle seal, a pressure cap, and an outer seal. The positioning ring is fitted between the upper and lower bearing seats of the active roller shaft and the box panel. A first flange extending outwards is provided on the outer surface of the right end. A flange has an external stop on its right end face, which is inserted into the inner hole of the lower bearing housing. The right end face of the first flange is sealed and fixedly connected to the left end face of the lower bearing housing. The locating ring has a first through hole, a first layer hole, and a second layer hole with the diameter increasing sequentially from right to left. The outer circle of the inner seal is interference-fitted into the first layer hole, with its right end face pressed against the right end face of the first layer hole, located at the right end of the locating ring. The outer circle of the middle seal is interference-fitted into the second layer hole, with its right end face pressed against the right end face of the second layer hole, located at the left end of the locating ring. The locating ring, the inner seal, and the middle seal are all connected together. The sealing components are integrally fitted onto the drive roller shaft. Both the inner and middle seals are interference-fitted with the drive roller shaft. The left end of the positioning ring is inserted into the housing panel, with its left end face aligned with the left side of the housing panel. The pressure cap has a second through hole, and a third layer of holes to the right of the second through hole. The outer seal is interference-fitted into the third layer of holes, forming an integral component with the pressure cap, which is also integrally fitted onto the drive roller shaft. The outer seal is interference-fitted with the drive 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 housing panel. The upper left end of the inner side of the outer seal has a first lip facing left, which is interference-fitted with the outer circular surface of the roller shaft. The left end of the inner side of the middle seal has a second lip facing left, and the middle of the inner side has a third lip facing left, both of which are interference-fitted with the outer circular surface of the roller shaft. The inner seal is a right-frame-shaped sealing ring with an opening on the left side. The left end of the inner side of the inner seal has a fourth lip facing right, and the right end of the inner side has a fifth lip facing right.The outer wall of the positioning ring has a radially threaded hole in the middle, which communicates with the first layer hole. An air sleeve is threaded into the first threaded hole. The air sleeve and the positioning ring are statically sealed by an O-ring. An air pipe is sealed to the upper end of the air sleeve. The other end of the air pipe is connected to an external air compressor. A pressure sensor is provided on the air pipe to deliver compressed air into the first layer hole, so that a pressure cavity is formed between the inner wall of the first layer hole, the outer surface of the driven roller shaft, the inner seal, and the middle seal. The pressure sensor monitors the air pressure in the pressure cavity as an early warning indicator of seal failure. The right end face of the pressure cover has a second annular sealing groove. A second O-ring is provided in the second annular sealing groove. The right end face of the pressure cover is sealed to the left end face of the positioning ring and is fixedly connected to the positioning ring by several first clamping screws. The driven roller assembly is located on the upper part of the support and includes a driven roller shaft, a driven gear, a second support bearing, and a driven pressure roller. The driven roller shaft is parallel to the driving roller shaft. The driven gear is installed at the right end of the driven roller shaft and meshes with the driving gear. There are two second support bearings, and the inner rings of the two second support bearings are respectively fastened to the outer circles of both ends of the driven roller shaft to support the driven roller shaft. The second support bearing is located in the upper bearing seat. The upper bearing seat is installed on the hydraulic floating device on the support, so that the driven roller assembly can float up and down with the hydraulic floating device. The position of the upper bearing seat is aligned with the lower bearing seat. The driven pressure roller is sleeved in the middle of the driven roller shaft and corresponds to the position of the driving pressure roller. A sealing structure as described in claim 1 is installed between the left and right sides of the roller pressing box on the driven roller shaft and the corresponding upper bearing seat. The active pressure roller and the driven pressure roller are provided with a second gap in the radial direction. The size of the second gap can be adjusted by adjusting the pressure of the hydraulic floating device. It is used to roll products of different thicknesses. The sealing ring and elastic sliding pad of the sealing structure form a sliding sealing structure when the hydraulic floating device is adjusted.

5. The roller pressing mechanism of a dry granulator according to claim 4, characterized in that: A pneumatic cavity is formed between the third lip, the fourth lip, the positioning ring, and the driving or driven roller shaft of the sealing structure. The calibrated gas pressure P0 of the gas filling the pneumatic cavity is set to 40% to 80% of the maximum pressure resistance of the cavity.

6. A method for early warning of sealing failure of the sealing structure of the roller pressing mechanism of a dry granulator as described in claim 4 or 5, characterized in that... Includes the following steps: S1. Working air pressure calibration: Cut off the second lip on the left side of the middle seal, apply soapy water around the roller shaft near the left side of the third lip, and gradually inflate the air chamber through an external air compressor via the air pressure sensor, air pipe, air jacket, and positioning ring. When the soapy water applied on the left side bubbles, it indicates that a leak has occurred at the third lip. Record the air pressure sensor value at this time. This value is the maximum pressure resistance value Pmax of the air chamber; working air pressure Po = 40%~80% Pmax; S2, Seal Failure Warning: The upper warning pressure Pu=1.1Po and the lower warning pressure Pd=0.9Po are set in the control system of the granulator. When the pressure inside the air chamber drops sharply and exceeds the lower limit of Pd, the control system of the granulator stops working, indicating that the first lip, the second lip and the third lip have all worn and failed, and lost the interference fit. S3. Handling of seal failure: Disassemble the seal structure for inspection. Use a tool microscope to observe the wear of the first lip, second lip, and third lip. Use a dimensional measuring instrument to measure the inner diameter of the first lip, second lip, and third lip. The measured inner diameter value is di. At this time, the driving roller or driven roller will also have corresponding slight wear. The corresponding measured outer diameter value of the driving roller or driven roller is do. Therefore, the interference of each lip after operation is obtained as: δ=(do-di) / 2. If the interference fit δ of each lip is less than 0, it can be determined that the outer seal and the middle seal need to be replaced; if the interference fit δ of each lip is greater than or equal to 0, check the external air compressor to ensure that the pressure is not too high.

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