Shaft end sealing device

Abstract

The utility model discloses a kind of shaft end sealing devices in the technical field of chemical production, including shell, shaft and sealing assembly, the shaft has first end and second end, shell has mating hole, the first end of shaft passes through mating hole and is located in shell, the second end of shaft is located outside shell, there is first cooperation gap between the outer circumferential side of shaft and the inner circumferential side of mating hole, sealing assembly is fixedly sleeved in the second end of shaft, for sealing first cooperation gap, at least one gas hole is set on sealing assembly, gas hole is communicated with first cooperation gap, gas hole is communicated with booster gas supply equipment, for into gas in first cooperation gap. The utility model solves the technical problem that the existing device has big security risk.

Description

Technical Field

[0001] This utility model relates to the field of chemical production technology, and in particular to a shaft end sealing device. Background Technology

[0002] The kneader is a crucial piece of equipment in the plasticization process of nitrocellulose, and its safety is paramount. The equipment mainly consists of a housing, a rotating shaft, and a sealing device. During operation, the first end of the shaft rotates within the housing, dispersing and plasticizing the fibrous nitrocellulose through a stirring component. The second end of the shaft passes through the housing and connects to the drive unit. Currently, a common sealing method involves installing a sealing gasket on the shaft, relying on its tight contact with the outer surface of the housing to prevent material leakage from inside the housing.

[0003] Because of the clearance between the shaft and the housing, during the kneading process, the nitrocellulose material is easily squeezed into the narrow clearance under strong physical pressure. The nitrocellulose will then be subjected to intense and continuous mechanical friction and compression between the rotating shaft and the stationary housing. This friction not only accelerates mechanical wear but also generates a large amount of heat locally. The nitrocellulose in the clearance accumulates heat in a confined environment, which may lead to its decomposition and ultimately cause combustion or explosion, posing a significant safety hazard. Utility Model Content

[0004] To address the significant safety hazards inherent in existing devices, this utility model provides a shaft end sealing device.

[0005] The technical solution adopted by this utility model to solve its technical problem is: A shaft end sealing device includes a housing, a rotating shaft, and a sealing assembly. The rotating shaft has a first end and a second end. The housing has a mating hole. The first end of the rotating shaft passes through the mating hole and is located inside the housing. The second end of the rotating shaft is located outside the housing. There is a first mating gap between the outer circumference of the rotating shaft and the inner circumference of the mating hole. The sealing assembly is fixedly sleeved on the second end of the rotating shaft to seal the first mating gap. The sealing assembly has at least one air inlet, which is connected to the first mating gap. The air inlet is connected to a pressurized air supply device for introducing gas into the first mating gap.

[0006] Furthermore, the sealing assembly includes a sealing gasket, which is fixedly sleeved on the second end of the rotating shaft. The end face of the sealing gasket is in close contact with the outer surface of the housing, and at least one air outlet is provided on the sealing gasket.

[0007] Furthermore, the air inlet of the air outlet is located on the outer peripheral side of the sealing gasket.

[0008] Furthermore, there are multiple air inlets, which are equidistantly distributed in a ring around the central axis of the sealing gasket.

[0009] Furthermore, the number of air inlets is 4 to 12, which are equidistantly distributed in a ring around the central axis of the sealing gasket.

[0010] Furthermore, the sealing assembly includes a sealing gasket and a bushing. The bushing is fixedly fitted on the second end of the rotating shaft, with its end face in contact with the outer surface of the housing. The sealing gasket is fixedly fitted on the bushing, with its end face in close contact with the outer surface of the housing. An air outlet is opened on the sealing gasket.

[0011] Furthermore, it also includes a fixing screw, the bushing is fixed to the rotating shaft by the fixing screw, there is a second fitting clearance between the inner circumference of the bushing and the outer circumference of the rotating shaft, the bushing is provided with a through hole, the air supply hole is connected to the second fitting clearance through the through hole, and the first fitting clearance is connected to the second fitting clearance.

[0012] Furthermore, a limiting component is fixedly installed on the bushing, and a compression spring is installed between the limiting component and the sealing gasket, with the compression spring acting on the limiting component and the sealing gasket respectively.

[0013] Furthermore, the limiting component is an annular sleeve with an internal thread inside, and the bushing has a corresponding external thread, with the annular sleeve and the bushing being threadedly connected.

[0014] Furthermore, it also includes a fixing sleeve, which is connected to the housing. The fixing sleeve is fitted onto the end of the bushing away from the housing, and the end face of the fixing sleeve contacts the limiting member to restrict the bushing from moving away from the housing.

[0015] Furthermore, the pressurized gas conveying equipment is an inert gas pressurized conveying equipment.

[0016] The beneficial effects of this utility model are: 1. This utility model provides an air inlet on the sealing assembly, which communicates with the first fitting gap. The air inlet is connected to a pressurized air supply device, allowing gas (such as inert gas) to be introduced into the first fitting gap. This airflow serves two key functions: first, it forms a positive pressure barrier, effectively preventing nitrocellulose material from intruding into the first fitting gap under pressure, thus eliminating the risk at its source; second, it actively purges and removes any material that may have entered or is present in trace amounts, ensuring no material residue remains in the first fitting gap, thereby eliminating the possibility of combustion and explosion due to frictional heat.

[0017] 2. The sealing assembly includes a sealing gasket, which is fixedly fitted (e.g., with an interference fit) on the rotating shaft, and an air inlet is provided on the sealing gasket to achieve dual sealing protection, namely mechanical seal and gas seal.

[0018] 3. The air inlet of the air supply port is located on the outer peripheral side of the sealing gasket, which facilitates the connection and arrangement of external air passages. This design avoids opening holes on the end face of the sealing gasket or the sealing surface in contact with the housing, ensuring the integrity of the sealing surface and the sealing effect.

[0019] 4. Multiple annularly distributed air inlets enable uniform and omnidirectional purging of the first mating gap. A single air inlet may create a dead zone for airflow, while the multi-hole annular arrangement ensures that airflow is uniformly injected into the first mating gap along the entire circumference, establishing a complete gas barrier without weak points, significantly improving the reliability of purging and sealing.

[0020] 5. By limiting the number of air inlets to 4 to 12 and distributing them equidistantly in a ring, the optimal balance is achieved between ensuring uniform purging and controlling processing complexity and air consumption. Too few inlets may lead to uneven purging, while too many inlets will increase processing costs and may weaken the structural strength of the sealing gasket.

[0021] 6. The sealing assembly includes a bushing and a sealing gasket. The bushing serves two main purposes: first, it protects the shaft by transferring the friction and potential wear of the shaft to the replaceable bushing, thus reducing the maintenance cost and difficulty of the shaft; second, the bushing can be made of copper or copper-aluminum alloy to avoid sparks generated by mechanical friction.

[0022] 7. There is a second fitting clearance between the inner circumference of the bushing and the outer circumference of the shaft. The bushing is fixed to the shaft by fixing screws. This design facilitates the disassembly and replacement of the bushing. In addition, it can also realize gas input to purge the first fitting clearance.

[0023] 8. By incorporating a compression spring, a continuous and stable automatic clamping force is provided to the sealing gasket. Even if the sealing gasket experiences normal wear during use, the compensating effect of the compression spring ensures that it always maintains tight contact with the outer surface of the housing, maintaining a stable sealing effect, avoiding the risk of leakage due to loosening of the clamping force, and reducing the workload required for frequent manual adjustment and maintenance.

[0024] 9. A threaded ring sleeve is used as the limiting component, which has a simple and reliable structure and is easy to install and disassemble. The axial position can be easily adjusted by rotating the ring sleeve, thereby controlling the preload of the compression spring, facilitating on-site installation, commissioning, and subsequent maintenance.

[0025] 10. The fixing sleeve plays a crucial role in axial positioning and support for the entire sealing assembly. It prevents the bushing from unexpected axial displacement or loosening due to vibration or rotational inertia during equipment operation, ensuring the long-term stability of the compression spring preload and sealing effect, and enhancing the reliability of the device.

[0026] 11. The pressurized gas conveying equipment is an inert gas pressurized conveying device, which further enhances safety and stability. Introducing inert gases such as helium not only purges the materials but also directly reduces the oxygen concentration in the gaps. Even in extreme abnormal situations that generate high temperatures, the inert environment can effectively inhibit combustion reactions, achieving dual safety assurance. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural schematic diagram of the shaft end sealing device of this utility model; Figure 2 This is a sectional view of the shaft end sealing device of this utility model; Figure 3 yes Figure 2 A magnified view of part A in the image; The markings in the diagram are as follows: 1-housing, 2-shaft, 3-first fitting clearance, 4-air inlet, 5-sealing gasket, 6-shaft sleeve, 7-second fitting clearance, 8-compression spring, 9-ring sleeve, 10-fixed sleeve. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the present invention will be further described below with reference to the accompanying drawings.

[0029] First, it should be stated that the technical solutions of the embodiments of this application are clearly and completely described. The described embodiments are only some of the embodiments of this application, and not a limitation of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0030] In the description of this utility model, it should be understood that the terms "first", "second", "upper", "lower", "left", "right", "inner", "outer", "axial" or "radial" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and are not intended to indicate or imply that the device or element referred to must have a specific orientation structure and operation. Therefore, they should not be construed as limitations on this utility model.

[0031] It should be noted that, in this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0032] Reference Figures 1 to 3 This utility model provides a shaft end sealing device.

[0033] like Figures 1 to 3 As shown, in some embodiments, a shaft end sealing device is provided, including a housing 1, a rotating shaft 2, and a sealing assembly. The rotating shaft 2 has a first end and a second end. The housing 1 has a mating hole. The first end of the rotating shaft 2 passes through the mating hole and is located inside the housing 1. The second end of the rotating shaft 2 is located outside the housing 1. There is a first mating gap 3 between the outer peripheral side of the rotating shaft 2 and the inner peripheral side of the mating hole. The sealing assembly is fixedly sleeved on the second end of the rotating shaft 2 for sealing the first mating gap 3. The sealing assembly has at least one air inlet 4, which is connected to the first mating gap 3. The air inlet 4 is connected to a pressurized air supply device for introducing gas into the first mating gap 3.

[0034] To connect the pressurized gas delivery device to the gas delivery port 4, a sealing shell is typically installed at the second end of the rotating shaft 2. This sealing shell is sealed to the housing 1. In this case, both the sealing assembly and the second end of the rotating shaft 2 are within the sealed cavity formed by the sealing shell and the housing 1. The pressurized gas delivery device is connected to the sealed cavity via a pipe. When pressurized gas is introduced into the sealed cavity, the gas naturally enters the first mating gap 3 through the gas delivery port 4. Alternatively, it can be connected to the gas delivery port 4 via a pipe. It should be noted that since the sealing assembly rotates with the rotating shaft 2, pipe entanglement and interference should be avoided. For example, a rotating mechanism can be installed; the specific structure can refer to existing technologies to avoid rotational interference. Alternatively, commercially available technologies can be used, as long as it ensures that the pressurized gas delivery device can supply gas into the gas delivery port 4.

[0035] For pressurized gas conveying equipment, a gas with a certain pressure should be introduced to ensure the purging of materials. The specific pressure is not strictly required; those skilled in the art can adjust and select it reasonably according to actual working conditions. The specific structure of the pressurized gas conveying equipment can refer to existing technology; there are no structural improvements here. Generally speaking, pressurized gas conveying equipment uses inert gases, such as helium, neon, and argon. Chemically inert gases, such as nitrogen, can also be used. In addition, other gases that do not react with nitrocellulose and are chemically inert can also be introduced.

[0036] This invention introduces a gas seal on top of a mechanical seal, which not only prevents material leakage but also prevents material from entering the first fitting gap 3. Specifically, this airflow forms a positive pressure barrier, effectively preventing nitrocellulose material from entering the first fitting gap 3 under compression, thus eliminating the risk at the source; secondly, it actively purges and removes any material that may have entered or is present in trace amounts, ensuring that there is no material residue in the first fitting gap 3, thereby eliminating the possibility of combustion and explosion caused by frictional heat.

[0037] In some embodiments, the sealing assembly includes a sealing gasket 5, which is fixedly sleeved on the second end of the rotating shaft 2. The end face of the sealing gasket 5 is in close contact with the outer surface of the housing 1, and at least one air outlet 4 is provided on the sealing gasket 5.

[0038] The sealing gasket 5 is generally tightly fitted on the rotating shaft 2, i.e., an interference fit, relying on the end face of the sealing gasket 5 to be in close contact with the outer surface of the housing 1 to seal the first fitting gap 3; in addition, a bushing 6 can also be fitted on the rotating shaft 2, and the sealing gasket 5 can be tightly fitted on the bushing 6, so that the sealing gasket 5 is indirectly fitted on the rotating shaft 2.

[0039] like Figures 1 to 3 As shown, regarding the location of the air inlet 4, it is preferable that the air inlet of the air inlet 4 is located on the outer peripheral side of the sealing gasket 5. This design facilitates the connection and arrangement of external air passages, avoids opening holes on the end face of the sealing gasket 5 or the sealing surface in contact with the housing 1, ensures the integrity and sealing effect of the sealing surface, and makes the air pipe connection operation more convenient. Of course, with slightly less effect, the air inlet 4 can also be opened on the end face of the sealing gasket 5 on the side away from the housing 1, which can also achieve gas input.

[0040] like Figures 1 to 3 As shown, the number of air inlets 4 is generally one or more. When the number of air inlets 4 is set to multiple, the multiple air inlets 4 are distributed in a ring around the central axis of the sealing gasket 5. This can be an equidistant distribution or a non-equidistant distribution. Setting multiple ring-shaped air inlets 4 can achieve uniform and all-round purging of the first mating gap 3. A single air inlet 4 may form a dead zone for airflow, while the multi-hole ring arrangement can ensure that the airflow is uniformly injected into the first mating gap 3 along the entire circumference, establishing a complete gas barrier without weak links, which significantly improves the reliability of purging and sealing.

[0041] Preferably, the number of air inlets 4 is 4 to 12, for example, 4, 8, 10 or 12. The multiple air inlets 4 are distributed equidistantly in a ring around the central axis of the sealing gasket 5. The equidistant distribution of the air inlets 4 in a ring further ensures the uniformity of the purging.

[0042] like Figures 1 to 3 As shown, in some embodiments, the sealing assembly includes a sealing washer 5 and a bushing 6. The bushing 6 is fixedly sleeved on the second end of the rotating shaft 2, and the end face of the bushing 6 is in contact with the outer surface of the housing 1. The sealing washer 5 is fixedly sleeved on the bushing 6, and the end face of the sealing washer 5 is in close contact with the outer surface of the housing 1. The air inlet 4 is opened on the sealing washer 5. Preferably, the air inlet of the air inlet 4 is located on the outer peripheral side of the sealing washer 5.

[0043] The bushing 6 can be made of copper or copper-aluminum alloy. Its purpose is twofold: first, it protects the shaft 2 by transferring the friction and potential wear of the shaft 2 to the replaceable bushing 6, thereby reducing the maintenance cost and difficulty of the shaft 2; second, the bushing 6 can be made of copper or copper-aluminum alloy to avoid sparks generated by mechanical friction.

[0044] The bushing 6 is fixedly fitted onto the second end of the rotating shaft 2. It can be an interference fit, with the air outlet 4 on the sealing gasket 5 connected to the first fitting clearance 3; or it can be a clearance fit secured with fixing screws. For example, it may also include fixing screws, with the bushing 6 fixed to the rotating shaft 2 by the fixing screws. A second fitting clearance 7 exists between the inner circumference of the bushing 6 and the outer circumference of the rotating shaft 2. A through hole is provided on the bushing 6, through which the air outlet 4 connects to the second fitting clearance 7, and the first fitting clearance 3 connects to the second fitting clearance 7. By connecting the air outlet 4 to the second fitting clearance 7 and the first fitting clearance 3 to the second fitting clearance 7, gas enters the through hole 4, then the second fitting clearance 7, and then the first fitting clearance 3. The purpose is to avoid creating a gas outlet on the sealing gasket 5, thus preserving the mechanical sealing performance of the sealing gasket 5. Since there is a second fitting clearance 7 between the bushing 6 and the rotating shaft 2, in order to prevent the bushing 6 from moving away from the housing 1, a threaded hole is opened on the rotating shaft 2, a screw through hole is opened on the bushing 6, the fixing screw passes through the screw through hole, the tail of the fixing screw is threadedly connected to the threaded hole, and the head of the fixing screw presses against the bushing 6 to prevent the bushing 6 from moving.

[0045] like Figures 1 to 3 As shown, in some embodiments, a limiting element is fixedly provided on the bushing 6, and a compression spring 8 is provided between the limiting element and the sealing gasket 5. The compression spring 8 acts on both the limiting element and the sealing gasket 5. By providing the compression spring 8, a continuous and stable automatic clamping force is provided to the sealing gasket 5. Even if the sealing gasket 5 experiences normal wear during use, the compensating effect of the compression spring 8 can ensure that it always maintains close contact with the outer surface of the housing 1, maintaining a stable sealing effect, avoiding the risk of leakage due to loosening of the clamping force, and reducing the workload of frequent manual adjustment and maintenance. The limiting element can be a limiting protrusion, an annular protrusion, or a threaded annular sleeve 9.

[0046] like Figures 1 to 3 As shown, preferably, the limiting component is an annular sleeve 9, which has an internal thread, and the bushing 6 has a corresponding external thread. The annular sleeve 9 and the bushing 6 are threadedly connected. The threaded connection and adjustable position of the annular sleeve 9 is simple and reliable in structure, and easy to install and disassemble. Its axial position can be easily adjusted by rotating the annular sleeve 9, thereby controlling the preload on the compression spring 8, which facilitates on-site installation, debugging and subsequent maintenance.

[0047] like Figures 1 to 3As shown, it also includes a fixing sleeve 10, which is connected to the housing 1. The fixing sleeve 10 is fitted onto the end of the bushing 6 away from the housing 1, and its end face contacts a limiting member to restrict the bushing 6 from moving away from the housing 1. The fixing sleeve 10 and the housing 1 can be directly connected or indirectly connected. For example, the fixing sleeve 10 can be fixedly connected to a gland, for example, by a pin, while the gland is fixedly connected to the housing 1. The fixing sleeve 10 is fitted onto the end of the bushing 6 away from the housing 1, and its end face can contact the bushing 6. Alternatively, a limiting member can be fixedly installed on the bushing 6, and its end face contacts the limiting member. When the bushing 6 and the rotating shaft 2 are interference-fitted, the fixing sleeve 10 can prevent the bushing 6 from shifting during equipment vibration. When the bushing 6 and the rotating shaft 2 are fixed by a fixing screw, the fixing sleeve 10 limits the bushing 6, and the fixing screw also limits the bushing 6, achieving double fixing protection.

[0048] like Figures 1 to 3 As shown, the pressurized gas conveying equipment is an inert gas pressurized conveying equipment, such as helium, neon or argon. The specific structure of the inert gas pressurized conveying equipment can refer to the existing technology, and there is no improvement to the structure here.

Claims

1. A shaft end sealing device, comprising a housing (1), a rotating shaft (2), and a sealing assembly, wherein the rotating shaft (2) has a first end and a second end, the housing (1) has a mating hole, the first end of the rotating shaft (2) passes through the mating hole and is located inside the housing (1), the second end of the rotating shaft (2) is located outside the housing (1), a first mating gap (3) exists between the outer circumference of the rotating shaft (2) and the inner circumference of the mating hole, and the sealing assembly is fixedly sleeved on the second end of the rotating shaft (2) for sealing the first mating gap (3), characterized in that: The sealing assembly has at least one air inlet (4), which is connected to the first fitting gap (3). The air inlet (4) is connected to a pressurized air supply device for introducing gas into the first fitting gap (3).

2. The shaft end sealing device as described in claim 1, characterized in that: The sealing assembly includes a sealing gasket (5), which is fixedly sleeved on the second end of the rotating shaft (2). The end face of the sealing gasket (5) is in close contact with the outer surface of the housing (1), and at least one air outlet (4) is provided on the sealing gasket (5).

3. The shaft end sealing device as described in claim 2, characterized in that: The air inlet of the air outlet (4) is located on the outer peripheral side of the sealing gasket (5).

4. The shaft end sealing device as described in claim 2, characterized in that: There are multiple air inlets (4), which are distributed equidistantly in a ring around the central axis of the sealing gasket (5).

5. The shaft end sealing device as described in claim 1, characterized in that: The sealing assembly includes a sealing gasket (5) and a bushing (6). The bushing (6) is fixedly sleeved on the second end of the rotating shaft (2). The end face of the bushing (6) is in contact with the outer surface of the housing (1). The sealing gasket (5) is fixedly sleeved on the bushing (6). The end face of the sealing gasket (5) is in close contact with the outer surface of the housing (1). The air outlet (4) is opened on the sealing gasket (5).

6. The shaft end sealing device as described in claim 5, characterized in that: It also includes fixing screws. The bushing (6) is fixed to the rotating shaft (2) by fixing screws. There is a second fitting clearance (7) between the inner circumference of the bushing (6) and the outer circumference of the rotating shaft (2). A through hole is opened on the bushing (6). The air supply hole (4) is connected to the second fitting clearance (7) through the through hole. The first fitting clearance (3) is connected to the second fitting clearance (7).

7. The shaft end sealing device as described in claim 5 or 6, characterized in that: A limiting component is fixedly installed on the bushing (6), and a compression spring (8) is provided between the limiting component and the sealing gasket (5). The compression spring (8) acts on the limiting component and the sealing gasket (5) respectively.

8. The shaft end sealing device as described in claim 7, characterized in that: a limiting member... The ring sleeve (9) has an internal thread, and the bushing (6) has an external thread. The ring sleeve (9) and the bushing (6) are threaded together.

9. The shaft end sealing device as described in claim 7, characterized in that: It also includes a fixing sleeve (10), which is connected to the housing (1). The fixing sleeve (10) is fitted on the end of the bushing (6) away from the housing (1). The end face of the fixing sleeve (10) is in contact with the limiting member to restrict the bushing (6) from moving away from the housing (1).

10. The shaft end sealing device as described in claim 1, characterized in that: The booster gas delivery equipment is an inert gas booster delivery equipment.

Images