A sealing structure employing a high-temperature carbon ring seal for a suspended bushing

Abstract

This invention discloses a sealing structure using a high-temperature carbon ring seal for a suspended bushing, relating to the field of bushing sealing technology. It includes a rotating shaft and a bushing fitted onto the rotating shaft. An elastic element is provided between the bushing and the rotating shaft, with a gap between them. The bushing is made of a metal or alloy with the same coefficient of thermal expansion as the carbon ring material. Using this solution, since the bushing and the carbon ring (graphite) have essentially the same coefficient of thermal expansion, when the unit's operating temperature rises, the portion of the main shaft's expansion exceeding that of the bushing is eliminated by the reserved gap. The bushing and the carbon ring expand synchronously, and the gap between them remains essentially constant from room temperature to operating temperature. This ensures that the leakage of sealing gas or process gas at room temperature and operating temperature remains essentially constant, effectively solving various problems associated with carbon ring seals in high-temperature, large-diameter units under room temperature conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shaft sleeve sealing, in particular to a sealing structure of a suspension type shaft sleeve sealed by high-temperature carbon rings. BACKGROUND

[0002] Currently, if a carbon ring is used for sealing of a high-temperature unit such as a compressor or a fan, the carbon ring is usually designed to directly cooperate with a main shaft or to be designed to cooperate with the main shaft in a small gap / interference fit with a shaft sleeve (having a similar thermal expansion coefficient to the main shaft). Due to the large difference in thermal expansion coefficients between the main shaft / the shaft sleeve (metal material) and the carbon ring (graphite material), when the unit operates at a high temperature (> 100℃) and the shaft diameter is large (> 200mm), the gap between the carbon ring and the main shaft at room temperature is large. When the unit is started (at room temperature), the sealing has the following defects:

[0003] 1. A large amount of sealing gas enters the unit and simultaneously leaks to the bearing side, which may affect the process gas composition in the unit or the lubrication of the bearing, and may damage the bearing.

[0004] 2. The sealing gas supply is insufficient, which causes the process gas to leak to the environment outside the unit, and affects the environment, personnel and equipment. Or the external gas enters the unit, which affects the process.

[0005] 3. The sealing gas supply system is large, the system manufacturing cost is increased, and the sealing gas consumption is increased.

[0006] 4. A large amount of process gas (without a sealing gas structure) leaks to the environment, which affects the environment, personnel and equipment.

[0007] Currently, the structure in which the shaft sleeve and the main shaft are cooperated in a gap usually adopts a tolerance band positioning, but the tolerance band has too large rigidity, and after a large amount of compression, the reset performance is poor, so that the diameter gap between the shaft sleeve and the main shaft positioned by the tolerance band cannot exceed 0.3mm, and the application range is greatly limited. SUMMARY

[0008] The present application aims to provide a sealing structure of a suspension type shaft sleeve sealed by high-temperature carbon rings, and the shaft sleeve and the carbon ring (graphite) have basically the same thermal expansion coefficient. When the operating temperature of the unit rises, the part of the main shaft that expands more than the expansion amount of the shaft sleeve is eliminated through the reserved gap. The shaft sleeve and the carbon ring expand synchronously, and the gap between the shaft sleeve and the carbon ring can basically remain unchanged from room temperature to the operating temperature, so that the leakage amount of the sealing gas (or the process gas) of the carbon ring sealing at room temperature and the operating temperature basically remains unchanged, and various problems of the carbon ring sealing at room temperature in the high-temperature and large-diameter unit are effectively solved.

[0009] The present application is realized by the following technical scheme:

[0010] The application discloses a sealing structure of a high-temperature carbon ring sealing suspension type shaft sleeve, which comprises a rotating shaft and a shaft sleeve sleeved on the rotating shaft, an elastic element is arranged between the shaft sleeve and the rotating shaft, and a gap is reserved.

[0011] In the prior art, due to the large difference between the thermal expansion coefficients of the main shaft / axle (metal material) and the carbon ring (graphite material), when the working temperature of the unit is high (>100 DEG C) and the shaft diameter is large (>200 mm), the gap between the carbon ring and the main shaft is large at normal temperature. However, the structure of the gap fit between the shaft sleeve and the main shaft usually adopts tolerance band positioning, but the rigidity of the tolerance band is too large, and the reset performance is poor after a large amount of compression, so that the diameter gap between the shaft sleeve and the main shaft positioned by the tolerance band cannot exceed 0.3 mm, and the application range is greatly limited. The application provides a sealing structure of a high-temperature carbon ring sealing suspension type shaft sleeve, and the specific scheme comprises a suspension type shaft sleeve, the shaft sleeve is sleeved on a rotating shaft and has a gap reserved between the shaft sleeve and the rotating shaft, the shaft sleeve and the rotating shaft can be connected through a key or a pin, and an elastic element is arranged between the shaft sleeve and the main shaft to support and position, so that a sufficient gap H is reserved, and the coaxiality of the shaft sleeve and the main shaft is kept within the allowable range; the shaft sleeve is made of a metal or an alloy which has a thermal expansion coefficient basically same as that of the carbon ring (graphite), and the surface of the shaft sleeve is hardened; the inner hole of the shaft sleeve and the main shaft reserve a sufficient gap H according to the thermal expansion difference of the two materials; the shaft sleeve and the carbon ring (graphite) expand synchronously, and the gap between the shaft sleeve and the carbon ring basically remains unchanged from normal temperature to working temperature, so that the leakage of the sealing gas (or process gas) of the carbon ring sealing at normal temperature and working temperature basically remains unchanged, and various problems of the carbon ring sealing of the high-temperature and large-diameter unit at normal temperature are effectively solved.

[0012] Further optimization is that the elastic element comprises a plurality of spring fixing seats, the end of the inner hole of the shaft sleeve is provided with a first installation groove in the length direction along the axial direction, and the plurality of spring fixing seats are arranged in the first installation groove and are uniformly distributed along the axial direction and the circumferential direction; one end of the spring fixing seat abuts against the side surface of the rotating shaft, the other end of the spring fixing seat is provided with a groove, the groove is provided with a first spiral spring, and the opening of the groove is provided with a first adjusting device connected with the first spiral spring; the first spiral spring can be radially stretched and contracted along the rotating shaft; the first adjusting device can be adjusted along the radial direction of the rotating shaft at the opening of the groove and abuts against the side wall of the first installation groove; the first adjusting device adopts a spring assembly transition cap; and the support and positioning of the elastic element are realized.

[0013] Further optimization is that the first installation groove in the inner hole of the shaft sleeve is provided with a first limiting mechanism, and the first limiting mechanism is used for limiting the axial displacement of the plurality of spring fixing seats.

[0014] Further optimization, the inner hole of the shaft sleeve is provided with a first installation slot at both ends, and a plurality of spring fixing seats are arranged in the first installation slot at both ends; by arranging a plurality of spring fixing seats at both ends, balanced support is realized.

[0015] Further optimization, the elastic element comprises a second spiral spring and a second adjusting device, a plurality of through holes are formed in the shaft sleeve side wall along the axial direction and the ring direction, the length direction of the through hole is arranged along the radial direction of the rotating shaft, the second spiral spring is arranged in the through hole, the second adjusting device is arranged at one end of the through hole away from the rotating shaft, one end of the second spiral spring is connected with the rotating shaft side wall, the other end of the second spiral spring is connected with the second adjusting device, the second spiral spring can be stretched and contracted along the radial direction of the rotating shaft, and the second adjusting device can be adjusted along the length direction of the through hole; the second adjusting device adopts an adjusting screw, and the adjusting screw is threadedly connected with the through hole; so as to realize the support and positioning of the elastic element.

[0016] Further optimization, the elastic element comprises a wave spring, second installation slots are formed at both ends of the inner hole of the shaft sleeve along the axial direction, and the wave spring is arranged in the second installation slot; the wave spring is sleeved on the rotating shaft, the wave trough of the wave spring abuts against the rotating shaft, and the wave crest of the wave spring abuts against the side wall of the second installation slot; so as to realize the support and positioning of the elastic element.

[0017] Further optimization, a second limiting mechanism is arranged in the second installation slot, and the second limiting mechanism is used for limiting the axial displacement of the wave spring.

[0018] Further optimization, the diameter gap 2H between the inner hole of the shaft sleeve and the main shaft is 2-3mm or more than 3mm; the inner hole of the shaft sleeve and the main shaft are provided with sufficient gap H according to the thermal expansion difference value of the two materials.

[0019] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0020] The present application provides a sealing structure of a high-temperature carbon ring sealing suspension type shaft sleeve, and the shaft sleeve and the carbon ring (graphite) have basically the same thermal expansion coefficient, when the working temperature of the unit rises, the part of the main shaft that expands more than the expansion amount of the shaft sleeve is eliminated through the reserved gap; the shaft sleeve and the carbon ring expand synchronously, and the gap between the shaft sleeve and the carbon ring can basically remain unchanged from normal temperature to working temperature, so that the leakage amount of the carbon ring sealing at normal temperature and working temperature of the sealing gas (or process gas) is basically unchanged, and various problems of the carbon ring sealing of the high-temperature and large-diameter unit at normal temperature are effectively solved. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to make the technical scheme of the exemplary embodiments of the present application clearer, the drawings needed in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope. Other related drawings can also be obtained by those of ordinary skill in the art without creative effort. In the drawings:

[0022] Figure 1 Partial sectional view of the sealing structure of an embodiment provided by the present application;

[0023] Figure 2 Enlarged view of the structure at B of an embodiment provided by the present application;

[0024] Figure 3 Partial sectional view of the sealing structure of an embodiment provided by the present application;

[0025] Figure 4 Partial sectional view of the sealing structure of an embodiment provided by the present application;

[0026] Figure 5 Structure schematic view of the wave spring of an embodiment provided by the present application.

[0027] Markings in the drawings and corresponding component names:

[0028] 1 - shaft sleeve, 2 - first coil spring, 3 - spring fixing seat, 4 - spring assembly transition cap, 5 - first limiting mechanism, 6 - adjusting screw, 7 - second coil spring, 8 - wave spring, 9 - second limiting mechanism. DETAILED DESCRIPTION

[0029] In order to make the technical scheme of the exemplary embodiments of the present application clearer, the drawings needed in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope. Other related drawings can also be obtained by those of ordinary skill in the art without creative effort. In the drawings:

[0030] Embodiment 1

[0031] This embodiment 1 provides a sealing structure of a high-temperature carbon ring sealing suspension type shaft sleeve 1, which comprises a rotating shaft and a shaft sleeve 1 sleeved on the rotating shaft. An elastic element is arranged between the shaft sleeve 1 and the rotating shaft, and a gap is left. The shaft sleeve 1 is made of a metal or alloy with the same thermal expansion coefficient as the carbon ring material.

[0032] With respect to the prior art, due to the large difference in the thermal expansion coefficients of the main shaft / bush 1 (metal material) and the carbon ring (graphite material), when the unit operating temperature is relatively high (>100℃) and the shaft diameter is relatively large (>200mm), the gap between the carbon ring and the main shaft at room temperature is relatively large. However, the structure of the gap fit between the bush 1 and the main shaft usually adopts tolerance band positioning, but the tolerance band has too large rigidity, and the reset performance is poor after a large amount of compression, which causes the diameter gap between the bush 1 and the main shaft positioned by the tolerance band to be less than 0.3mm, and the application range is greatly limited. The present scheme provides a sealing structure of a high-temperature carbon ring sealing suspension type bush 1, and in the specific scheme, the suspension type bush 1 is sleeved on the rotating shaft and has a gap with the rotating shaft. The bush 1 and the rotating shaft can be connected through a key or a pin, and an elastic element is used for supporting and positioning between the bush 1 and the main shaft, so as to reserve a sufficient gap H and keep the coaxiality of the bush 1 and the main shaft within a permissible range. The bush 1 is made of a metal or an alloy having a thermal expansion coefficient basically the same as that of the carbon ring (graphite), and the surface of the bush 1 is hardened. The inner hole of the bush 1 and the main shaft reserve a sufficient gap H according to the difference in the thermal expansion of the two materials. Since the thermal expansion coefficients of the bush 1 and the carbon ring are basically the same, when the operating temperature of the unit rises, the part of the main shaft that expands more than the expansion of the bush 1 is eliminated through the reserved gap. The bush 1 and the carbon ring expand synchronously, and the gap between the bush 1 and the carbon ring basically remains unchanged from room temperature to the operating temperature, so that the leakage of the sealing gas (or process gas) of the carbon ring sealing at room temperature and the operating temperature basically remains unchanged, thereby effectively solving various problems of the carbon ring sealing of the high-temperature and large-diameter unit at room temperature.

[0033] In the embodiment, the diameter gap 2H between the inner hole of the bush 1 and the main shaft is 2-3mm or more than 3mm. The bush 1 is made of a metal or an alloy having a thermal expansion coefficient basically the same as that of the carbon ring (graphite), and the surface of the bush 1 is hardened. The inner hole of the bush 1 and the main shaft reserve a sufficient gap H according to the difference in the thermal expansion of the two materials. The diameter gap (2H) can be 2-3mm or more, and the bush 1 and the main shaft are supported and positioned by an elastic element, so as to keep the coaxiality of the bush 1 and the main shaft within a permissible range.

[0034] Embodiment 2

[0035] The embodiment 2 is further optimized on the basis of the embodiment 1, and provides a structure of the elastic element, as shown in Figure 1 and Figure 2 .

[0036] Please refer to Figure 1 and Figure 2As a specific embodiment of the support positioning of the elastic element, the elastic element is provided with a plurality of spring fixing seats 3, the inner hole end of the shaft sleeve 1 is provided with a first installation slot in the length direction along the axial direction, and the plurality of spring fixing seats 3 are arranged in the first installation slot and are uniformly distributed along the axial direction and the circumferential direction; one end of the spring fixing seat 3 abuts against the side surface of the rotating shaft, the other end of the spring fixing seat 3 is provided with a groove, the groove is provided with a first spiral spring 2, the opening of the groove is provided with a first adjusting device connected with the first spiral spring 2, and the first spiral spring 2 can be expanded and contracted along the radial direction of the rotating shaft; the first adjusting device can be adjusted along the radial direction of the rotating shaft at the opening of the groove and abut against the side wall of the first installation slot; the first adjusting device adopts a spring assembly transition cap 4.

[0037] It can be understood that in the embodiment, the shaft sleeve 1 and the rotating shaft are provided with a plurality of spring fixing seats 3, the plurality of spring fixing seats 3 are arranged in the first installation slot at the end of the shaft sleeve 1 and are uniformly distributed along the axial direction and the circumferential direction, thereby supporting in the circumferential direction, the lower end of the spring fixing seat 3 abuts against the rotating shaft, the upper end is provided with the first adjusting device at the opening of the groove and abuts against the inner side of the first installation slot, the first adjusting device adjusts the position of itself along the radial direction of the rotating shaft, thereby changing the support height, can be adjusted according to the predetermined gap between the shaft sleeve 1 and the rotating shaft, and positioning is realized; in the adjusting process, the first spiral spring 2 is always in a compressed state, thereby generating a corresponding thrust force on the spring fixing seat 3, and supporting through the elastic element; wherein the first adjusting device is a spring assembly transition cap 4, the spring assembly transition cap 4 is assembled through transition, thereby always being able to exceed the spring fixing seat 3 and abut against the first installation slot.

[0038] Please refer to Figure 1 As a specific embodiment for preventing the spring fixing seat 3 from moving along the axial direction, the first installation slot in the inner hole of the shaft sleeve 1 is provided with a first limiting mechanism 5, and the first limiting mechanism 5 is used to limit the axial displacement of the plurality of spring fixing seats 3.

[0039] It can be understood that in the embodiment, the plurality of spring fixing seats 3 can be formed by a whole fixing seat, a plurality of grooves are arranged on the fixing seat along the axial direction, that is, adjacent spring fixing seats 3 are a whole structure, or adjacent spring fixing seats 3 can be closely arranged; the first installation slot in the inner hole of the shaft sleeve 1 is provided with a first limiting mechanism 5, the first limiting mechanism 5 can be a ring, a ring-shaped stopper or other limiting devices, thereby limiting the plurality of spring fixing seats 3 in the first installation slot, and preventing the spring fixing seat 3 from moving along the axial direction.

[0040] As a redundancy scheme, the inner hole of the shaft sleeve 1 is provided with a first installation slot at both ends, and the first installation slots at both ends are provided with a plurality of spring fixing seats 3; by arranging a plurality of spring fixing seats 3 at both ends, balanced support is realized.

[0041] Embodiment 3

[0042] This embodiment 3 is further optimized on the basis of embodiment 1, and provides a structure of the elastic element, as shown in Figure 3

[0043] Please refer to Figure 3 , as a specific embodiment of realizing the support and positioning of the elastic element, it is provided that the elastic element comprises a second coil spring 7 and a second adjusting device, a plurality of through holes are formed in the side wall of the shaft sleeve 1 along the axial and annular directions, the length direction of the through holes is arranged along the radial direction of the rotating shaft; the second coil spring 7 is arranged in the through hole, and the second adjusting device is arranged at one end of the through hole away from the rotating shaft; one end of the second coil spring 7 is connected to the side wall of the rotating shaft, and the other end of the second coil spring 7 is connected to the second adjusting device; the second coil spring 7 can be expanded and contracted along the radial direction of the rotating shaft, and the second adjusting device can be adjusted along the length direction of the through hole; the second adjusting device adopts an adjusting screw 6, and the adjusting screw 6 is threadedly connected to the through hole;

[0044] It can be understood that in this embodiment, a plurality of through holes are formed in the side wall of the shaft sleeve 1, and the plurality of through holes are uniformly distributed along the axial and annular directions; the second coil spring 7 is arranged in the through hole, and the positioning and support are realized through the adjustment of the second adjusting device; wherein the lower end of the second coil spring 7 abuts or is fixed on the rotating shaft, and the upper end is connected to the second adjusting device; the second adjusting device is an adjusting screw 6, and is threadedly connected to the through hole; by screwing the adjusting screw 6, the depth of the adjusting screw 6 is changed, the predetermined gap between the shaft sleeve 1 and the rotating shaft is adjusted, and the positioning is realized; during the adjustment process, the second coil spring 7 is always in a compressed state, so as to generate a corresponding thrust force on the spring fixing seat 3, and the support is realized through the elastic element.

[0045] Embodiment 4

[0046] This embodiment 4 is further optimized on the basis of embodiment 1, and provides a structure of the elastic element, as shown in Figure 4 and Figure 5

[0047] Please refer to Figure 4 and Figure 5 , as a specific embodiment of realizing the support and positioning of the elastic element, it is provided that the elastic element comprises a wave spring 8, second installation grooves are formed in both ends of the inner hole of the shaft sleeve 1 along the axial direction, and the wave spring 8 is arranged in each second installation groove; the wave spring 8 is sleeved on the rotating shaft, the trough of the wave spring 8 abuts against the rotating shaft, and the peak of the wave spring 8 abuts against the side wall of the second installation groove; in this embodiment, the elastic element is arranged as the wave spring 8, the wave spring 8 is sleeved on the rotating shaft and located in the second installation groove, so as to abut against the rotating shaft through the trough of the wave spring 8 and abut against the shaft sleeve 1 through the peak of the wave spring 8, thereby realizing the positioning and support of the shaft sleeve 1.

[0048] ​​As a redundancy scheme, the second installation slot is provided with a second limiting mechanism 9, which is used to limit the axial displacement of the wave plate spring 8; the second limiting mechanism 9 can be a limiting device such as a collar, an annular stopper, etc., so as to limit the wave plate spring 8 in the second installation slot and prevent the wave plate spring 8 from being displaced in the axial direction.

[0049] The above specific embodiments further explain the purposes, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A sealing structure with high-temperature carbon ring sealing suspension bushing, comprising a rotating shaft and a bushing (1) sleeved on the rotating shaft, characterized in that, The elastic element is arranged between the shaft sleeve (1) and the rotating shaft, and a gap is left; the shaft sleeve is made of metal with the same thermal expansion coefficient as carbon ring material; The elastic element comprises a plurality of spring fixing seats (3), the inner hole end of the shaft sleeve (1) is provided with a first installation groove in the length direction along the axial direction, and the plurality of spring fixing seats (3) are arranged in the first installation groove and are uniformly distributed along the axial direction and the circumferential direction; one end of the spring fixing seat (3) abuts against the side surface of the rotating shaft, the other end of the spring fixing seat (3) is provided with a groove, the first coil spring (2) is arranged in the groove, the first adjusting device connected with the first coil spring (2) is arranged at the opening of the groove, and the first coil spring (2) can be expanded and contracted along the radial direction of the rotating shaft; the first adjusting device can be adjusted along the radial direction of the rotating shaft at the opening of the groove and abut against the side wall of the first installation groove.

2. The seal structure of claim 1, wherein the high-temperature carbon ring seal is a floating bushing seal. The first adjusting device adopts a spring assembly transition cap (4).

3. The seal structure of claim 1, wherein the high temperature carbon ring seal is a floating bushing seal. The first limiting mechanism (5) is arranged in the first installation groove of the inner hole of the shaft sleeve (1), and is used for limiting the axial displacement of the plurality of spring fixing seats (3).

4. The seal structure of claim 1, wherein the high temperature carbon ring seal is a floating bushing seal. The inner hole of the shaft sleeve (1) is provided with the first installation groove at both ends, and the first installation groove at both ends is provided with a plurality of spring fixing seats (3).

5. The seal structure of claim 1, wherein the high temperature carbon ring seal is a floating bushing seal. The elastic element comprises a second coil spring (7) and a second adjusting device, the side wall of the shaft sleeve (1) is provided with a plurality of through holes in the axial direction and the circumferential direction, and the length direction of the through hole is arranged along the radial direction of the rotating shaft; the second coil spring (7) is arranged in the through hole, and the second adjusting device is arranged at one end of the through hole away from the rotating shaft; one end of the second coil spring (7) is connected with the side wall of the rotating shaft, the other end of the second coil spring (7) is connected with the second adjusting device, the second coil spring (7) can be expanded and contracted along the radial direction of the rotating shaft, and the second adjusting device can be adjusted along the length direction of the through hole.

6. A seal structure employing a high-temperature carbon ring seal floating bushing according to claim 5, wherein The second adjusting device adopts an adjusting screw (6), and the adjusting screw (6) is threadedly connected with the through hole.

7. The seal structure of claim 1 wherein the high temperature carbon ring seal is a floating bushing. The elastic element comprises a wave spring (8), the inner hole of the shaft sleeve is provided with a second installation groove arranged in the axial direction at both ends, the wave spring (8) is arranged in the second installation groove at both ends, the wave spring (8) is sleeved on the rotating shaft, the trough of the wave spring (8) abuts against the rotating shaft, and the peak of the wave spring (8) abuts against the side wall of the second installation groove.

8. The seal structure of claim 7, wherein the high-temperature carbon ring seal is a floating bushing seal. The second limiting mechanism (9) is arranged in the second installation groove, and is used for limiting the axial displacement of the wave spring (8).

9. The seal structure of claim 1 wherein the high temperature carbon ring seal is a floating bushing. The diameter gap 2H between the inner hole of the shaft sleeve and the rotating shaft is 2-3 mm or more than 3 mm.

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