Elastic air force sealing device for spiral feeder shaft cantilever bearing

Abstract

The utility model belongs to the biomass, garbage power generation industry especially relates to a kind of elastic pneumatic sealing device for spiral feeder shaft cantilever bearing.The spiral shaft is worn on the box bulkhead, and the spiral shaft outer sleeve is equipped with cantilever bearing in the left side of feed tank box bulkhead, and the shaft neck outer edge from the right end surface of box bulkhead to the root of spiral shaft is sequentially provided with four fluorine gasket, positioning flange and multilayer fan-shaped stainless steel elastic sealing sheet group from left to right, fan-shaped stainless steel elastic sealing sheet is installed together using staggered lamination form, compressed air connector is connected with positioning flange reserved channel in the perforation, the multilayer fan-shaped stainless steel elastic sealing sheet group is established at the root of spiral shaft in the application, and the positive pressure state of air chamber space makes the tiny combustion particles close to the root of spiral shaft be blown away by air pressure difference, guarantees that the root of spiral shaft cannot be accumulated, extruded and burned particles, prevents tiny particles from entering into the bearing chamber in the left side of box bulkhead;To extend the service life of cantilever bearing and spiral feeding shaft.

Description

Technical Field

[0001] This utility model belongs to the biomass and waste-to-energy industry, and specifically relates to an elastic pneumatic sealing device for a cantilever bearing of a screw feeder shaft. Background Technology

[0002] Cantilever screw feeders are a primary application in rural biomass power generation, waste-to-energy power generation, and thermal power generation, commonly used for conveying granular and powdery combustible materials. These feeders operate in extremely harsh environments; boiler combustion chambers typically reach temperatures exceeding 900 degrees Celsius. Heat conduction accelerates the aging of felt seals and rubber-framed oil seals, reducing bearing lifespan. During material conveying, frequent alternation between forward and reverse rotation causes irregular materials, fine dust, and impurities to accumulate at the junction of the cantilever shaft and the partition. These impurities and material particles enter the bearing chamber, accelerating wear and aging of the bearings and related components, severely impacting their lifespan. Summary of the Invention

[0003] The purpose of this utility model is to overcome the above-mentioned technical deficiencies and provide an elastic pneumatic sealing device for cantilever bearings of screw feeder shafts that has a simple structure and increases the service life of cantilever bearings.

[0004] The technical solution adopted by this utility model to solve the technical problem is an elastic pneumatic sealing device for a cantilever bearing of a screw feeder shaft, including a screw shaft, a cantilever bearing, and a housing partition. The screw shaft is mounted on the housing partition. A cantilever bearing is fitted around the screw shaft on the left side of the housing partition. A felt strip seal and a rubber skeleton oil seal are also installed outside the screw shaft for sealing the bearing. The part of the screw shaft connected to the partition on the right side of the housing partition is designated as the root of the screw shaft. The distance from the right end face of the housing partition to the root of the screw shaft... From left to right, the outer edge of the journal of the shaft is provided with a PTFE gasket, a positioning flange, and a multi-layer fan-shaped stainless steel elastic sealing sheet assembly. The fan-shaped stainless steel elastic sealing sheets are installed together in a staggered and overlapping manner. The outer ring of the outermost fan-shaped stainless steel elastic sealing sheet assembly is connected and fixed to the positioning flange. The multi-layer fan-shaped stainless steel elastic sealing sheet assembly and the positioning flange are fastened together with bolts. The multi-layer fan-shaped stainless steel elastic sealing sheet assembly, the positioning flange, and the PTFE gasket are fastened and fixed to the right end face of the feed box partition with bolts. The multi-layer fan-shaped stainless steel elastic sealing sheet assembly is folded to the right and fixed together in a staggered and overlapping manner, forming an air chamber space between it and the root of the spiral shaft. A radial pre-tightening displacement is left between the rightmost opening end of the multi-layer fan-shaped stainless steel elastic sealing sheet assembly and the outer edge of the spiral shaft root. A positioning flange reserved groove is opened between the positioning flange and the right end face of the box partition. The positioning flange reserved groove connects inward to the air chamber space enclosed between the multi-layer fan-shaped stainless steel elastic sealing sheet assembly and the root of the spiral shaft. On the feed box partition, corresponding to the positioning flange, the positioning flange is fixed together in a staggered and overlapping manner. A perforation is made at the location of the reserved groove of the positioning flange. A compressed air pipe is inserted into the perforation to connect to the reserved groove of the positioning flange. The other end of the compressed air pipe is connected to the compressed air pump on the outside of the left side of the box partition. The positioning flange that forms the reserved groove of the positioning flange is sealed and fastened to the right end face of the feeding box partition with bolts, so that the reserved groove of the positioning flange is sealed into a cavity. The compressed air pumped out by the compressed air pump enters the air chamber space through the compressed air pipe and the reserved groove of the positioning flange, so that the air chamber space forms a positive pressure state.

[0005] The beneficial effect of using an elastic pneumatic sealing device for the cantilever bearing of the screw feeder shaft is that: Traditional biomass power generation, waste-to-energy power generation, and thermal power generation primarily use fine particles such as granules and powders as combustion materials. When the material enters the material drive device from the system's feeding device, the screw feeder may momentarily reverse direction when adjusting the boiler's combustion conditions. At this time, the fine material will move in the opposite direction of the conveying direction, reaching the root of the screw shaft of the screw feeder connected to the right end of the feed box partition in the combustion chamber. Over time, the particles to be burned will accumulate there. The pressure generated at the root of the screw shaft enters the bearing chamber on the left side of the feed box partition through the gap between the screw shaft and the partition, thus accelerating the aging and wear of the cantilever bearing and related accessories. The operating temperature in the boiler furnace combustion chamber is usually 850-950℃. During the boiler combustion process, the high-temperature flue gas will reach the partition and the root of the screw shaft. Through heat conduction, the bearing chamber on the left side of the partition will operate at a high temperature. The high temperature will cause the rubber seals and other bearing-related components to age and fail quickly, resulting in a shortened bearing service life.

[0006] This application establishes a multi-layered fan-shaped stainless steel elastic sealing sheet assembly at the root of the spiral shaft connected to the right end of the housing partition. The elastic sealing sheet assembly, together with the PTFE gasket and positioning flange, is fastened to the right end face of the housing partition. The multi-layered fan-shaped stainless steel elastic sealing sheet assembly is folded to the right to form an air chamber space with the root of the spiral shaft connected to the right end of the housing partition. A right positioning flange is provided with a reserved groove on the right end face of the housing partition. Compressed air at 20°C pumped out by the external compressed air pump is continuously delivered to the air chamber space through the groove, keeping the air chamber space under positive pressure. The positive pressure state of the air chamber space causes the small combustion particles near the root of the spiral shaft to be blown away by the air pressure difference, ensuring that the small particles to be burned do not accumulate or squeeze at the root of the spiral shaft, and preventing the small particles from entering the bearing chamber on the left side of the housing partition. The continuous input of 20°C compressed gas ensures that the temperature of the air chamber space and the root of the spiral shaft can always be maintained at a certain low temperature, thereby ensuring that the spiral shaft and the bearing chamber on the left side of the housing partition are not damaged by the high temperature generated by heat conduction, and extending the service life of the bearing. The elastic sealing sheets are arranged in a fan shape and installed in a staggered, overlapping manner, with three layers of sheets forming a good seal. The sealing sheet assembly is tightly fitted to the root of the screw shaft and the housing partition via positioning flanges and PTFE gaskets, creating a good isolation effect and forming an air chamber space. The sealing sheets are elastic and have a rebound function. Each sealing sheet is staggered and overlapping, with overlapping marks between each sheet. A pre-tightening displacement is left between the opening of the sealing sheet assembly and the outer edge of the screw shaft root. This ensures that the circumferential swing of the screw shaft is within normal operating range, and also allows the positive pressure air within the air chamber space to blow out fine particles that have entered the air chamber space from the pre-tightening gaps and the overlapping gaps between the multiple layers of elastic sealing sheets, thereby extending the service life of the cantilever bearing and the screw feed shaft. Attached Figure Description

[0007] The following description, in conjunction with the accompanying drawings, illustrates specific embodiments.

[0008] Figure 1 This is a front view of the structure of the elastic pneumatic sealing device for the cantilever bearing of the screw feeder shaft.

[0009] Figure 2 yes Figure 1 AA view.

[0010] Figure 3 This is a cross-sectional structural diagram of an elastic pneumatic sealing device for a cantilever bearing on a screw feeder shaft.

[0011] Figure 4 This is a structural view of a conventional screw feeder.

[0012] Figure 5 yes Figure 3 Right side view of the center positioning flange.

[0013] Figure 6 yes Figure 3 Enlarged partial cross-sectional view of the connection between the multi-layer fan-shaped stainless steel elastic sealing sheet assembly and the box partition.

[0014] Figure 7 yes Figure 3 Assembly diagram of a single-layer, fan-shaped stainless steel elastic sealing sheet installed in a staggered, stacked manner.

[0015] Figure 8 yes Figure 3 A structural view of the interlayer PTFE gasket that provides a sealing function between each layer of fan-shaped stainless steel elastic sealing sheet group.

[0016] Figure 9 This is a schematic diagram of the swing amplitude of the feeding screw shaft equipped with an elastic pneumatic sealing device.

[0017] Figure 10 It is a structural diagram of the material drive, material feeding, and material combustion in the overall combustion working system.

[0018] Figure 11 yes Figure 10 The enlarged view at point I is the structural view of the root of the helical shaft before modification.

[0019] Figure 12 yes Figure 3 Structural view after adding an elastic pneumatic sealing device to the root of the central spiral shaft.

[0020] Figure 13 yes Figure 5 Sectional view along the BB direction.

[0021] In the diagram, 1-combustion feed pipe; 2-screw feeder; 3-boiler furnace combustion chamber; 4-screw shaft; 5-screw shaft root; 6-cantilever bearing; 7-box partition; 8-felt strip seal; 9-rubber skeleton oil seal; 10-PTFE gasket; 11-positioning flange; 12-fan-shaped stainless steel elastic sealing sheet; 13-interlayer PTFE gasket; 14-overlapping mark; 15-gas chamber space; 16-positioning flange reserved groove; 17-compressed air connection pipe; a-screw shaft circumferential swing value. Detailed Implementation

[0022] Example, see attached document Figure 4 , Figure 10 , Figure 11 ,in Figure 4 This is a working view of a traditional integrated combustion system for biomass power generation, waste-to-energy, and thermal power generation. A motor-driven screw feeder 2 is located on the left side of the feed box partition 7. The screw feeder shaft 4 of the screw feeder 2 is mounted on the feed box partition 7. A bearing chamber is located at the connection point between the screw shaft 4 and the left end face of the partition 7. The screw shaft is mounted in a bearing within the bearing chamber. A felt seal 8 and a rubber-reinforced oil seal 9 are also provided outside the screw shaft 4 for sealing. The output end of the screw shaft 4 is located on the right side of the feed box partition 7. In the boiler, the portion where the spiral shaft 4 connects to the right end of the housing partition 7 is designated as the spiral shaft root 5. An auger blade is installed on the outer edge of the spiral shaft at its output end. The rotation of the spiral shaft causes the auger blade to convey material to the combustion chamber 3. (Details omitted as they are well-known and publicly available technologies.) Above the output end of the spiral shaft 4 is a fuel discharge pipe 1. Biomass pellets, waste, and thermal power generation pellets fall from the fuel discharge pipe 1 and are fed into the boiler combustion chamber 3 via the auger blades at the output end of the spiral shaft 4 for combustion and power generation. The flue gas generated by the boiler combustion can reach temperatures as high as 850-950℃. The flue gas can travel along the output end of the spiral shaft 4 to the spiral shaft root 5 and the feeding housing partition 7. The high temperature, through heat conduction, heats the spiral shaft 4 and related components in the outer bearing chamber on the left side of the housing partition 7. This high temperature accelerates the wear of the components, thus reducing the service life of the bearings. Due to the forward and reverse rotation of the screw shaft 4, the fine particles to be burned falling from the fuel discharge pipe 1 are squeezed into the area between the right end face of the housing partition 7 and the root 5 of the screw shaft. As the cantilever screw shaft 4 rotates, it will generate a circumferential swing value 'a', which is generally ±50mm. A gap will be generated between the screw shaft 4 and the housing partition 7. The fine particles to be burned squeezed into the area at the root 5 of the screw shaft will enter the bearing chamber through these small gaps, accelerating the wear of the bearing components and reducing the service life of the bearing.

[0023] See attached document Figure 1-3 , Figure 5-9 , Figure 12 The screw feeder shaft cantilever bearing uses an elastic pneumatic sealing device. The screw shaft 4 is mounted on the housing partition 7. A cantilever bearing 6 is fitted around the screw shaft 4 on the left side of the housing partition 7. A felt strip seal 8 and a rubber skeleton oil seal 9 are also installed on the outside of the screw shaft 4 for bearing sealing. The part of the screw shaft 4 connected to the housing partition 7 on the right side is designated as the screw shaft root 5. From the right end face of the housing partition 7 to the outer edge of the journal of the screw shaft root 5, from left to right, there are PTFE gaskets 10, positioning flanges 11, and three-layer fan-shaped stainless steel elastic sealing sheets 12. Each fan-shaped stainless steel elastic sealing sheet 12 is installed in a staggered overlapping manner, and each fan-shaped stainless steel elastic sealing sheet 12 has staggered overlapping marks 14. Figure 7 As shown, instead of a single circular elastic sealing sheet, multiple fan-shaped stainless steel elastic sealing sheets are staggered and stacked. This ensures a good seal and also provides small gaps between each sealing sheet, allowing the high-pressure compressed gas in the final gas chamber space 15 to be blown out through these gaps, thereby increasing the dispersion area for the surrounding particles to be burned and enhancing the dispersion effect. After each layer of sealing sheet is stacked, the three layers of sealing sheet are fastened and fixed with bolts to ensure their fixing and sealing effect. Positioning flanges 11 are provided on both sides of the portion of the three-layer fan-shaped stainless steel elastic sealing sheet 12 that is parallel to the right end face of the housing partition 7 for positioning and limitation. A PTFE gasket 10 is provided on the left side of the positioning flange 11. The PTFE gasket 10, positioning flange 11, three-layer fan-shaped stainless steel elastic sealing sheet 12, and the outermost positioning flange 11 are fastened to the right end face of the housing partition 7 from left to right with bolts. Interlayer PTFE gaskets 13 are also provided between the three-layer fan-shaped stainless steel elastic sealing sheet 12 groups. The interlayer PTFE gaskets 13 are fan-shaped to match the stainless steel elastic sealing sheets, forming a toothed closure to increase the sealing effect. The three-layer fan-shaped stainless steel elastic sealing sheet 12 groups are folded to the right and staggered and stacked together, forming an air chamber space 15 between them and the root 5 of the spiral shaft. (Refer to the attached diagram.) Figure 6The normal pre-bending angle is 125°, but the actual installed angle is 130°. There is a radial pre-tightening displacement between the rightmost opening end of the 12 sets of three-layer fan-shaped stainless steel elastic sealing sheets and the outer edge of the root 5 of the screw shaft. Because the design length of the screw shaft of the cantilever feeder is generally about 2.5-4m, the maximum circumferential swing value 'a' of the screw shaft is 50mm. After calculation using trigonometric functions, the maximum circumferential swing at the root of the screw shaft is 3-4mm. Therefore, this radial pre-tightening displacement is required. The value of this radial pre-tightening displacement is 5mm. The fan-shaped stainless steel sealing sheets are elastic and have a certain elastic deformation characteristic. When extremely special conditions occur, they can also produce corresponding elastic deformation. The positioning flange 11 extends outward, and a positioning flange reserved groove 16 is opened between the extended part and the right end face of the box partition 7. The positioning flange reserved groove 16 is connected inward to the air chamber space 15 formed between the multi-layer fan-shaped stainless steel elastic sealing sheet 12 and the root of the spiral shaft 5. A through hole is opened on the feeding box partition 7 at the position corresponding to the positioning flange reserved groove 16. The compressed air pipe 17 passes through the through hole and connects to the positioning flange reserved groove 16. The other end of the compressed air pipe 17 is connected to the compressed air pump on the left side of the box partition 7. The positioning flange forming the positioning flange reserved groove 16 is sealed and fastened to the right end face of the feeding box partition 7 by bolts, so that the positioning flange reserved groove 16 is sealed into a cavity. The compressed air pumped out by the compressed air pump enters the air chamber space 15 through the compressed air pipe 17 and the positioning flange reserved groove 16, so that the air chamber space is in a positive pressure state. The compressed air pump continuously pumps compressed air at approximately 20°C. This 20°C compressed air enters the air chamber space 15 through the compressed air pipe 17 and the reserved groove 16 of the positioning flange, maintaining the temperature within the air chamber space 15 within the operating temperature range of approximately 20°C. This resists heat conduction from the approximately 900°C flue gas blown from the boiler furnace combustion chamber 3, thus protecting the components in the bearing chamber on the left side of the housing partition 7 from damage caused by high-temperature conduction and increasing the service life of the bearings. The compressed air in the air chamber space 15 is under positive pressure. The high-pressure gas is blown outward through the 5mm radial pre-tightening displacement orifice and the gaps between the multi-layer fan-shaped stainless steel elastic seals 12, causing the fine particles to be burned that are rushing towards the root of the spiral shaft 5 to be blown away. This ensures that the root of the spiral shaft 5 is not accumulated or squeezed by fine particles, thereby extending the service life of the bearing chamber.

[0024] In its actual production operations, the applicant has not used the combustion system of the biomass power generation company that uses the technical solution of this application. The feed screw shafts in front of the furnace consist of 8 shafts, and the bearings are replaced about 10 times a year on average. The service life is generally half a year, and some need to be replaced after only 3 months. After applying the elastic pneumatic sealing device of this application, the system has been running stably for a year. During the shutdown inspection, it was found that there was no ash accumulation or large particles of solidified sludge inside the bearings, and the bearing clearance did not increase significantly. This significantly extended the service life of the bearings, ensured the stable operation time of the unit, and increased power generation revenue.

Claims

1. An elastic pneumatic sealing device for a cantilever bearing of a screw feeder shaft, comprising a screw shaft (4), a cantilever bearing (6), and a housing partition (7), characterized in that, The spiral shaft (4) is mounted on the box partition (7). A cantilever bearing (6) is fitted on the spiral shaft (4) on the left side of the feeding box partition (7). A felt strip seal (8) and a rubber skeleton oil seal (9) are also sealed on the spiral shaft (4). The part of the spiral shaft (4) connected to the partition on the right side of the feeding box partition (7) is set as the spiral shaft root (5). From the right end face of the box partition (7) to the outer edge of the journal of the spiral shaft root (5), a PTFE gasket (10), a positioning flange (11) and a multi-layer fan-shaped gasket are arranged from left to right. The outermost fan-shaped stainless steel elastic sealing sheet (12) group is connected and fixed to the positioning flange (11). The multi-layer fan-shaped stainless steel elastic sealing sheet (12) group is fastened and fixed to the positioning flange (11) with fastening bolts. The PTFE gasket (10), the multi-layer fan-shaped stainless steel elastic sealing sheet (12) group and the positioning flange (11) are fastened and fixed to the right end face of the feed box partition (7) with bolts. The multi-layer fan-shaped stainless steel elastic sealing sheet (12) group is folded to the right and connected to the root of the spiral shaft. (5) A gas chamber space (15) is formed between them. A positioning flange reserved groove (16) is opened between the positioning flange (11) and the right end face of the box partition (7). The positioning flange reserved groove (16) is connected inward to the gas chamber space (15) formed between the multi-layer fan-shaped stainless steel elastic sealing sheet (12) group and the root of the spiral shaft (5). A through hole is opened on the feeding box partition (7) at the position corresponding to the positioning flange reserved groove (16). The compressed air pipe (17) passes through the through hole and connects to the positioning flange. The other end of the reserved channel (16) and the compressed air pipe (17) are connected to the compressed air pump on the outside of the left side of the box partition. The positioning flange (11) that forms the reserved channel (16) is sealed and fastened to the right end face of the feed box partition (7) by bolts, so that the reserved channel (16) of the positioning flange is sealed into a cavity. The compressed air pumped out by the compressed air pump enters the air chamber space (15) through the compressed air pipe (17) and the reserved channel (16) of the positioning flange, so that the air chamber space (15) forms a positive pressure state.

2. The elastic pneumatic sealing device for the cantilever bearing of the screw feeder shaft according to claim 1, characterized in that, The multi-layer fan-shaped stainless steel elastic sealing sheet (12) is folded to the right and fixed together in a staggered stacking form.

3. The elastic pneumatic sealing device for the cantilever bearing of the screw feeder shaft according to claim 1, characterized in that, A radial preload displacement is left between the rightmost opening end of the multi-layer fan-shaped stainless steel elastic sealing sheet (12) group and the outer edge of the root of the spiral shaft (5).

4. The elastic pneumatic sealing device for the cantilever bearing of the screw feeder shaft according to claim 2, characterized in that, The angle at which it folds to the right is 130°.

5. The elastic pneumatic sealing device for the cantilever bearing of the screw feeder shaft according to claim 3, characterized in that, The radial preload displacement is 5 mm.

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