A zero-leakage combined shaft seal device for high-temperature and high-dust working conditions

Abstract

The present invention relates to the technical field of shaft seals, and specifically discloses a zero-leakage combined shaft seal device for high-temperature and high-dust working conditions. Among them, the fixed-end combined seal device is sleeved on the drive end on the left side of the rotating shaft, and the sliding-end combined seal device is arranged at the other end on the right side of the rotating shaft, symmetrically arranged relative to the pyrolysis reactor with the fixed-end combined seal device; when the sliding-end limiting mechanism rotates together with the rotating shaft, the sliding-end double mechanical seal rotates synchronously with the sliding-end limiting mechanism through a smooth guide rod. The present invention can achieve stable and reliable operation of the shaft seal when the ambient temperature is 500°C to 1200°C, the shaft span is 10 to 15 meters long, and the diameter is more than 400 mm, ensuring zero leakage of solid heat carrier particles, dust, and toxic gases in the pyrolysis reactor.

Description

Technical Field

[0001] The invention belongs to the technical field of shaft sealing, and in particular relates to a zero-leakage combined shaft sealing device for high-temperature and high-dust working conditions. Background Art

[0002] The pyrolysis reactor is the key core equipment in the domestic waste pyrolysis system. It plays the role of conveying, mixing and stirring domestic waste and solid heat carrier. Under the action of high-temperature heat carrier, domestic waste is decomposed into CO, H 2 S.H. 2 The whole system is in an oxygen-free environment of about 500-1200℃ and the solid heat carrier is fine particles. The long axis span of the pyrolysis reactor will cause vibration during operation. There is a certain amount of gas leakage. The pyrolysis gas overflows the reactor and pollutes the surrounding environment and forms an explosive gas environment. The air entering the pyrolysis reactor will cause combustion. Therefore, the pyrolysis reactor requires zero leakage for the performance of the shaft sealing device, and the shaft sealing environment conditions are harsh. The commonly used shaft seals for high temperatures at home and abroad are mainly packing seals and mechanical seals.

[0003] The packing seal has a simple structure and requires low machining accuracy for the shaft, but its sealing performance is poor. The packing gland needs to be tightened frequently during use. It has poor stability and cannot be completely sealed. When used in a pyrolysis reactor, it is easy for flammable and explosive toxic pyrolysis gas to leak out. It also consumes too much power and is not suitable as a sealing device for the rotating shaft of a pyrolysis reactor.

[0004] Although mechanical seals have good sealing performance and high stability, simple mechanical seals are directly exposed to and seal high-temperature solid heat carriers in pyrolysis reactors, and high-temperature solid heat carriers can easily enter the seal, causing damage to the seal. After the mechanical seal is damaged, the water used to cool the mechanical seal can easily enter the pyrolysis reactor, which will have a great impact on the pyrolysis process. In addition, in a high-temperature environment, the long axis is prone to expansion and radial runout, which will cause extrusion and imbalance between the dynamic and static rings of the traditional mechanical seal, thereby causing damage to the mechanical seal. Therefore, traditional mechanical seals cannot be used as sealing devices for pyrolysis reactors.

[0005] Therefore, it is urgent to provide a new sealing device to meet the sealing requirements of the pyrolysis reactor shaft. Summary of the invention

[0006] The object of the present invention is to provide a zero-leakage combined shaft sealing device for high-temperature and high-dust working conditions, which has good sealing performance and high stability in a high-temperature environment.

[0007] The technical solution of the present invention is as follows:

[0008] A zero-leakage combined shaft seal device for high-temperature and high-dust working conditions is used to seal the gap Q between the double rotating shafts of the pyrolysis reactor and the pyrolysis reactor shell, preventing harmful gases from escaping; it includes a fixed-end combined seal device and a sliding-end combined seal device;

[0009] The fixed-end combined seal device is sleeved on the driving end on the left side of the rotating shaft, and includes a fixed-end isolating gas seal, a fixed-end multi-stage labyrinth seal, a fixed-end brush seal, a fixed-end double mechanical seal, and a fixed-end limiting mechanism;

[0010] The sliding-end combined seal device is arranged at the other end on the right side of the rotating shaft, and is symmetrically arranged with the fixed-end combined seal device relative to the pyrolysis reactor. It includes a sliding-end isolating gas seal, a sliding-end reverse-thread seal, a sliding-end brush seal, a sliding-end double mechanical seal, and a sliding-end limiting mechanism.

[0011] The sliding-end isolating gas seal and the fixed-end isolating gas seal have the same structure, the sliding-end multi-stage labyrinth seal and the fixed-end multi-stage labyrinth seal have the same structure, the sliding-end brush seal and the fixed-end brush seal have the same structure, the sliding-end double mechanical seal and the fixed-end double mechanical seal have the same structure, and the fixed-end limiting mechanism and the sliding-end limiting mechanism have different structures.

[0012] The fixed-end isolating gas seal is the first seal where the fixed-end combined seal device contacts the pyrolysis reactor shell; the fixed-end isolating gas seal is in a ring shape and is sleeved on the rotating shaft; an air supply channel is processed on the ring, the air inlet of the air supply channel is located on the outer ring side surface of the ring, and the air outlet is located on one end surface of the ring; the air inlet of the fixed-end isolating gas seal is communicated with the isolating gas supply end, and the air outlet is directly opposite to the gap Q, communicating the isolating gas supply end and the gap Q; the isolating gas is an inert gas that does not react with the sealing medium, and the isolating gas pressure is not more than 10 kPa higher than the internal pressure of the pyrolysis reactor.

[0013] The fixed-end multi-stage labyrinth seal is processed on the inner ring side wall of the annular cavity of the fixed-end isolating gas seal and contacts the rotating shaft to form the second seal; the fixed-end multi-stage labyrinth seal has 4 to 5 throttle tooth gaps; the distance between each throttle tooth gap is 1 mm, and the gap between each throttle tooth gap and the shaft is 0.5 mm.

[0014] The fixed-end brush seal is composed of an annular brush, is located on the left side of the fixed-end isolating gas seal, and is connected to the fixed-end isolating gas seal by bolts to form the third seal; the brush filaments adopt nanotechnology, and high-temperature resistant lubricating grease is coated on the brush filaments, which will not cause scratches on the rotating shaft during long-term operation, and can also compensate for the gap generated by the rotation shaft jump. The thickness of the annular brush is 5 mm.

[0015] The fixed-end double-ended mechanical seal is located on the left side of the fixed-end brush seal, and the two are connected by bolts. The fixed-end double-ended mechanical seal includes a cooling water chamber, a balance tank, and two sets of dynamic rings and static rings provided on both sides of the cooling water chamber. One set on the right side of the cooling water chamber is set as dynamic ring A and static ring A, and one set on the left side of the cooling water chamber is set as dynamic ring B and static ring B. Both dynamic ring A and static ring A adopt a double-hard surface seal design with cemented carbide materials. Dynamic ring B is made of cemented carbide, and static ring B is made of graphite material, which is a combination of hard and soft surface seal design. At the same time, dynamic ring B is connected to the dynamic ring seat of the fixed-end double-ended mechanical seal by bolts. The balance tank is connected to the cooling water chamber through a hose and is placed outside the combined seal device as a water storage tank. At the same time, the water storage tank has a liquid level alarm device.

[0016] The fixed-end limit mechanism is of a ring structure, located on the left side of the fixed-end double-ended mechanical seal, sleeved on the rotating shaft and radially fastened by fastening screws, and at the same time fixed together with the left side of the dynamic ring seat of the fixed-end double-ended mechanical seal by screws.

[0017] The sliding-end limit mechanism is of a ring structure, located on the right side of the sliding-end double-ended mechanical seal, and radially fastened on the rotating shaft by fastening screws; a groove is machined axially on the outer ring of the sliding-end limit mechanism for limiting the smooth guide rod.

[0018] One end of the smooth guide rod is fixed to the right side of the dynamic ring seat of the sliding-end double-ended mechanical seal by threads, and the middle part of the smooth guide rod is clamped in the groove on the sliding-end limit mechanism.

[0019] When the sliding-end limit mechanism rotates together with the rotating shaft, the fixed-end double-ended mechanical seal rotates synchronously with the sliding-end limit mechanism through the smooth guide rod.

[0020] The remarkable effects of the present invention are as follows:

[0021] (1) The isolation gas seal and the multi-stage labyrinth seal of the present invention can ensure that a large amount of high-temperature gas dust will not enter the subsequent seal system, and the brush seal can adapt to a certain amount of shaft runout to ensure that solid dust particles will not enter the subsequent double-ended mechanical seal, and the double-ended mechanical seal can ensure zero leakage of pyrolysis gas.

[0022] (2) The auxiliary system of the present invention includes a balance tank and an alarm device to ensure that the cooling water in the double-ended mechanical seal will not enter the equipment interior after the device is damaged, affecting the overall operation of the equipment.

[0023] (3) The combined seal device of the present invention is divided into two forms: fixed-end and sliding-end. By making different structural designs on the limit mechanism, the thermal expansion amount of the rotating shaft can be moved in the direction of the sliding end, so that the combined seal device can work stably when the thermal expansion shaft elongates.

[0024] (4) The combined sealing device of the present invention includes an isolation gas seal, a multi-stage labyrinth seal, a brush seal, a double-end face seal, a limiting mechanism, and an auxiliary system, which can achieve stable and reliable operation of the shaft seal when the ambient temperature is 500°C to 1200°C, the shaft span is 10 to 15 meters long, and the diameter is more than 400 mm, ensuring zero leakage of solid heat carrier particles and dust and toxic gases in the pyrolysis reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of the upper half of the combined sealing device of the present invention;

[0026] Figure 2 is a schematic diagram of the fixed-end limiting mechanism;

[0027] Figure 3 is a schematic diagram of the sliding-end limiting mechanism.

[0028] In the figure: 1 is the fixed-end combined sealing device; 2 is the sliding-end combined sealing device; 11 is the fixed-end isolation gas seal; 12 is the fixed-end multi-stage labyrinth seal; 13 is the fixed-end brush seal; 14 is the fixed-end double-end face mechanical seal; 141 is the moving ring seat of the fixed-end double-end face mechanical seal; 15 is the fixed-end limiting mechanism; 21 is the sliding-end isolation gas seal; 22 is the sliding-end multi-stage labyrinth seal; 23 is the sliding-end brush seal; 24 is the sliding-end double-end face mechanical seal; 241 is the moving ring seat of the sliding-end double-end face mechanical seal; 25 is the sliding-end limiting mechanism; 251 is the sliding-end limiting mechanism before shaft expansion; 252 is the sliding-end limiting mechanism after shaft expansion; 26 is the smooth guide rod. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] As Figure 1 shown, a zero-leakage combined shaft seal device for high-temperature and high-dust working conditions includes a fixed-end combined sealing device 1 and a sliding-end combined sealing device 2. There are two rotating shafts in the pyrolysis reactor that can transport and mix solid heat carriers and domestic waste. The combined sealing device of the present invention is used to seal the gap Q between the double rotating shafts and the outer shell of the pyrolysis reactor to prevent harmful gases from escaping.

[0031] The fixed-end combined sealing device 1 is sleeved on the driving end on the left side of the rotating shaft and includes a fixed-end isolation gas seal 11, a fixed-end multi-stage labyrinth seal 12, a fixed-end brush seal 13, a fixed-end double-end face mechanical seal 14, and a fixed-end limiting mechanism 15.

[0032] The fixed end isolation gas seal 11 is the first seal between the fixed end combined sealing device 1 and the outer shell of the pyrolysis reactor. The fixed end isolation gas seal 11 is in the shape of a ring and is sleeved on the rotating shaft. A gas supply channel is processed on the ring, and the air inlet of the gas supply channel is located on the outer ring side of the ring, and the air outlet is located on one side end face of the ring. The air inlet of the fixed end isolation gas seal 11 is connected with the isolation gas supply end, and the air outlet is directly opposite to the gap Q, connecting the isolation gas supply end and the gap Q. By introducing isolation gas into the air supply channel of the fixed end isolation gas seal 11, a positive pressure is formed in the gap Q, and the high-temperature solid heat carrier escaping from the inside of the pyrolysis reactor into the gap Q is blown out, and at the same time, the high-temperature gas of the pyrolysis reactor is prevented from entering the fixed end combined sealing device 1 to destroy the combined sealing device, so as to form a good seal. The isolation gas is any one of N2, CO2, and water vapor, and the isolation gas pressure is no more than 10kpa higher than the internal pressure of the pyrolysis reactor.

[0033] The fixed end multi-stage labyrinth seal 12 is processed on the inner ring side wall of the annular cavity of the fixed end isolation gas seal 11 and contacts the rotating shaft. The fixed end multi-stage labyrinth seal 12 has 4 to 5 throttling tooth gaps, each throttling tooth gap has a spacing of 1mm, and the gap between each throttling tooth gap and the shaft is 0.5mm. Due to the turbulent mixing of the airflow, when the pyrolysis gas mixed with solid heat carrier passes through the fixed end labyrinth seal 12, part of the kinetic potential energy will be converted into heat energy, and the kinetic potential energy will be reduced, thereby achieving the purpose of sealing and forming a second seal.

[0034] The fixed end brush seal 13 is composed of a 5 mm thick annular brush, located on the left side of the fixed end isolation gas seal 11, and connected to the fixed end isolation gas seal 11 by bolts. The brush wire of the fixed end brush seal 13 adopts nano-level technology, and is coated with high temperature resistant lubricating grease. It will not scratch the rotating shaft during long-term operation, and can compensate for the gap caused by the vibration of the rotating shaft to form a third seal.

[0035] The fixed end double-face mechanical seal 14 is located on the left side of the fixed end brush seal 13, and the two are connected by bolts. The fixed end double-face mechanical seal 14 includes a cooling water chamber, a balance tank, and two groups of dynamic rings and static rings arranged on both sides of the cooling water chamber. The cooling water chamber is sleeved on the rotating shaft, wherein a group on the right side of the cooling water chamber is set as a dynamic ring A and a static ring A, both of which adopt a double hard surface sealing design of cemented carbide materials; a group on the left side of the cooling water chamber is set as a dynamic ring B and a static ring B, the dynamic ring B adopts cemented carbide, and the static ring B adopts graphite material. Such a soft and hard combination of sealing structure can ensure that the fixed end double-face mechanical seal 14 can operate stably in the environment of high-temperature solid heat carriers. The dynamic ring B is connected to the fixed end double-face mechanical seal dynamic ring seat 141 by bolts.

[0036] Circulating cooling water is introduced into the cooling water chamber to ensure that the temperature inside the fixed-end double mechanical seal 14 does not exceed the limit, preventing the O-ring inside the fixed-end double mechanical seal 14 from being damaged by high temperature, so that it can operate stably and safely in a high-temperature environment. The balance tank is connected to the cooling water chamber through a hose and is placed outside the combined seal device as a water storage tank. At the same time, there is a liquid level alarm device on the water outlet tank. Once the cooling water leaks, it will enter the balance tank. When the liquid level reaches the warning line, the system will alarm, which can prevent the cooling water from leaking into the gap Q formed between the pyrolysis reactor shell and the fixed combined seal device 1 through the fixed-end brush seal 13 and the fixed-end multi-stage labyrinth seal 12, and further prevent the cooling water from entering the pyrolysis reactor.

[0037] As Figure 2 shown, the fixed-end limiting mechanism 15 is of an annular structure, located on the left side of the fixed-end double mechanical seal 14, sleeved on the rotating shaft and radially fastened by fastening screws, and at the same time fixed to the left side of the moving ring seat 141 of the fixed-end double mechanical seal by screws. It can not only ensure the synchronous rotation of the rotating shaft and the fixed-end combined seal device 1, but also ensure that after the driving end on the left side of the rotating shaft expands due to heat, the direction of the expansion amount can be transmitted to the other end on the right side of the rotating shaft, so that the fixed-end combined seal device 1 will not be affected by thermal stress.

[0038] The sliding-end combined seal device 2 is arranged at the other end on the right side of the rotating shaft, symmetrically arranged with the fixed-end combined seal device 1 with respect to the pyrolysis reactor, and includes a sliding-end isolating gas seal 21, a sliding-end reverse-thread seal 22, a sliding-end brush seal 23, a sliding-end double mechanical seal 24 and a sliding-end limiting mechanism 25.

[0039] The sliding-end isolating gas seal 21 and the fixed-end isolating gas seal 11 have the same structure, the sliding-end multi-stage labyrinth seal 22 and the fixed-end multi-stage labyrinth seal 12 have the same structure, the sliding-end brush seal 23 and the fixed-end brush seal 13 have the same structure, and the sliding-end double mechanical seal 24 and the fixed-end double mechanical seal 14 have the same structure.

[0040] The sliding-end limiting mechanism 25 is of an annular structure, located on the right side of the sliding-end double mechanical seal 24, and radially fastened to the rotating shaft by fastening screws. A groove is machined axially on the outer ring of the sliding-end limiting mechanism 25 for limiting the smooth guide rod 26.

[0041] One end of the smooth guide rod 26 is fixed to the right side of the moving ring seat 241 of the sliding-end double mechanical seal by threads, and the middle part of the smooth guide rod 26 is clamped in the groove on the sliding-end limiting mechanism 25. When the sliding-end limiting mechanism 25 rotates with the rotating shaft, the sliding-end double mechanical seal 24 rotates synchronously with the sliding-end limiting mechanism 25 through the smooth guide rod 26. AsFigure 3 As shown, after the rotating shaft expands due to heat, the double-end face mechanical seal 24 at the sliding end and the sliding-end limit mechanism 25 axially slide relative to each other through the smooth guide rod 26 to offset the influence brought by the high temperature on the rotating shaft.

Claims

1. A zero-leakage combined shaft seal device for high-temperature and high-dust working conditions, characterized in that: it is used to seal the gap Q between the double rotating shafts of the pyrolysis reactor and the outer shell of the pyrolysis reactor to prevent harmful gases from escaping; it includes a fixed-end combined seal device (1) and a sliding-end combined seal device (2); the fixed-end combined seal device (1) is sleeved on the driving end on the left side of the rotating shaft, and includes a fixed-end isolation gas seal (11), a fixed-end multi-stage labyrinth seal (12), a fixed-end brush seal (13), a fixed-end double mechanical seal (14) and a fixed-end limiting mechanism (15); the sliding-end combined seal device (2) is arranged at the other end on the right side of the rotating shaft, and is symmetrically arranged with the fixed-end combined seal device (1) relative to the pyrolysis reactor, and includes a sliding-end isolation gas seal (21), a sliding-end multi-stage labyrinth seal (22), a sliding-end brush seal (23), a sliding-end double mechanical seal (24) and a sliding-end limiting mechanism (25); the fixed-end isolation gas seal (11) is the first seal in contact with the outer shell of the pyrolysis reactor of the fixed-end combined seal device (1); the fixed-end isolation gas seal (11) is in a circular ring shape and is sleeved on the rotating shaft; an air supply channel is processed on the circular ring, the air inlet of the air supply channel is located on the outer ring side surface of the circular ring, and the air outlet is located on one end surface of the circular ring; the air inlet of the fixed-end isolation gas seal (11) is communicated with the isolation gas supply end, and the air outlet is facing the gap Q, communicating the isolation gas supply end and the gap Q; the isolation gas is an inert gas that does not react with the sealing medium, and the isolation gas pressure is not more than 10 kPa higher than the internal pressure of the pyrolysis reactor; the fixed-end multi-stage labyrinth seal (12) is processed on the inner ring side wall of the annular cavity of the fixed-end isolation gas seal (11) and is in contact with the rotating shaft to form the second seal; the fixed-end multi-stage labyrinth seal (12) has 4 to 5 throttling tooth gaps; the distance between each throttling tooth gap is 1 mm, and the gap between each throttling tooth gap and the shaft is 0.5 mm; the fixed-end brush seal (13) is composed of an annular brush, is located on the left side of the fixed-end isolation gas seal (11), and is connected to the fixed-end isolation gas seal (11) by bolts to form the third seal; the brush filaments adopt nanotechnology, and high-temperature resistant lubricating grease is coated on the brush filaments, which will not scratch the rotating shaft during long-term operation, and at the same time can compensate for the gap generated by the rotation shaft jump, and the thickness of the annular brush is 5 mm; The fixed-end double-ended mechanical seal (14) is located on the left side of the fixed-end brush seal (13), and the two are connected by bolts. The fixed-end double-ended mechanical seal (14) includes a cooling water chamber, a balance tank, and two sets of dynamic rings and static rings provided on both sides of the cooling water chamber. One set on the right side of the cooling water chamber is set as dynamic ring A and static ring A, and one set on the left side of the cooling water chamber is set as dynamic ring B and static ring B. Both dynamic ring A and static ring A adopt a double-hard surface seal design with cemented carbide materials. Dynamic ring B is made of cemented carbide, and static ring B is made of graphite material for a soft-hard surface combined seal design. At the same time, dynamic ring B is connected to the dynamic ring seat (141) of the fixed-end double-ended mechanical seal by bolts. The balance tank is connected to the cooling water chamber through a hose and is placed outside the combined seal device as a water storage tank. At the same time, the water storage tank has a liquid level alarm device. The fixed-end limiting mechanism (15) is of an annular structure, located on the left side of the fixed-end double-ended mechanical seal (14), sleeved on the rotating shaft and fastened radially by fastening screws, and is fixed to the left side of the dynamic ring seat (141) of the fixed-end double-ended mechanical seal by screws at the same time. The sliding-end limiting mechanism (25) is of an annular structure, located on the right side of the sliding-end double-ended mechanical seal (24), and is fastened radially on the rotating shaft by fastening screws. A groove is machined axially on the outer ring of the sliding-end limiting mechanism (25) for limiting the smooth guide rod (26).

2. A zero-leakage combined shaft seal device for high-temperature and high-dust working conditions as described in claim 1, characterized in that: The sliding-end isolation gas seal (21) and the fixed-end isolation gas seal (11) have the same structure, the sliding-end multi-stage labyrinth seal (22) and the fixed-end multi-stage labyrinth seal (12) have the same structure, the sliding-end brush seal (23) and the fixed-end brush seal (13) have the same structure, the sliding-end double-ended mechanical seal (24) and the fixed-end double-ended mechanical seal (14) have the same structure, and the fixed-end limiting mechanism (15) and the sliding-end limiting mechanism (25) have different structures.

3. A zero-leakage combined shaft seal device for high-temperature and high-dust working conditions as described in claim 1, characterized in that: One end of the smooth guide rod (26) is fixed to the right side of the dynamic ring seat (241) of the sliding-end double-ended mechanical seal by threads, and the middle of the smooth guide rod (26) is clamped in the groove on the sliding-end limiting mechanism (25).

4. A zero-leakage combined shaft seal device for high-temperature and high-dust working conditions as described in any one of claims 1 to 3, characterized in that: When the sliding-end limiting mechanism (25) rotates together with the rotating shaft, the sliding-end double-ended mechanical seal (24) rotates synchronously with the sliding-end limiting mechanism (25) through the smooth guide rod (26).

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