CN117469370B - Dry gas sealing device free of isolation gas - Google Patents
Dry gas sealing device free of isolation gas Download PDFInfo
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- CN117469370B CN117469370B CN202311814244.9A CN202311814244A CN117469370B CN 117469370 B CN117469370 B CN 117469370B CN 202311814244 A CN202311814244 A CN 202311814244A CN 117469370 B CN117469370 B CN 117469370B
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- 238000007789 sealing Methods 0.000 title claims abstract description 109
- 238000002955 isolation Methods 0.000 title claims abstract description 53
- 230000003068 static effect Effects 0.000 claims abstract description 124
- 230000000903 blocking effect Effects 0.000 claims abstract description 6
- 230000002441 reversible effect Effects 0.000 abstract description 7
- 239000003921 oil Substances 0.000 description 29
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 10
- 238000000034 method Methods 0.000 description 9
- 230000008569 process Effects 0.000 description 9
- 230000002829 reductive effect Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 6
- 229910002092 carbon dioxide Inorganic materials 0.000 description 5
- 239000001569 carbon dioxide Substances 0.000 description 5
- 239000000306 component Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000006837 decompression Effects 0.000 description 4
- 238000000227 grinding Methods 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 230000004323 axial length Effects 0.000 description 3
- 238000011144 upstream manufacturing Methods 0.000 description 3
- 239000008358 core component Substances 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 244000126211 Hericium coralloides Species 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
Abstract
The invention provides a dry gas sealing device free of isolation gas, which comprises a rotating shaft, a shaft sleeve and a sealing cylinder body, wherein the shaft sleeve is sleeved on the rotating shaft, the shaft sleeve is fixedly connected with the rotating shaft, a movable ring is fixedly arranged on the shaft sleeve, the sealing cylinder body is rotatably arranged on the rotating shaft, a static ring seat is arranged on the sealing cylinder body, a static ring is slidably arranged on the static ring seat, the static ring is elastically connected with the bottom of the static ring seat through an elastic device, an auxiliary piece for blocking the static ring from sliding towards the bottom of the static ring seat is arranged at the bottom of the static ring seat, one end of the auxiliary piece is fixedly connected with the static ring seat, an interval exists between the other end of the auxiliary piece and the static ring, and the movable ring is tightly attached to the static ring. According to the invention, the oil gas reverse string in the downstream gear box can be effectively isolated without using additional isolation gas, and a compressed air source is not required to be additionally configured, so that the purposes of simplifying the system structure, reducing the power consumption of the system and improving the system efficiency are achieved.
Description
Technical Field
The invention relates to the technical field of dynamic sealing devices, in particular to a dry gas sealing device free of isolation gas.
Background
Among the shaft end dynamic sealing modes, the dry gas sealing effectively seals by utilizing the fluid dynamics principle, the dynamic and static gaps only have a few micrometers in normal operation, the leakage quantity is about 1/30 of that of comb teeth, and the dynamic and static sealing mode is quite effective.
The dry gas seal consists of a movable ring, a static ring core component and auxiliary components such as a sealing ring, a spring, a static ring seat, a shaft sleeve and the like which are matched with the movable ring and the static ring core component. The sealing surface of the dry gas sealing dynamic ring is ground and polished, and fluid dynamic pressure grooves with special functions are processed on the sealing surface. When the dry gas seal ring rotates, seal gas is sucked into the dynamic pressure groove, and the radial component flows toward the seal weir from the outer diameter toward the center. The gas pressure entering the sealing surface increases due to the pumping effect of the sealing weir, thereby further separating the moving ring from the stationary ring.
In order to avoid damage to the sealing surface caused by backflow of oil gas in a downstream gear box of the system to the sealing surface, the dry gas sealing device always needs to introduce a stream of isolation airflow to isolate downstream oil gas. However, the introduction of the isolation air flow requires that the system be configured with a compressed air source or that the air flow be extracted from the main loop of the operating system, which inevitably results in a more complex overall configuration of the dry gas seal, while the extraction of the air flow from the main loop of the operating system as the isolation air reduces the working capacity and the working efficiency of the working medium, both of which can make the whole operating system particularly complex and have reduced effects.
Disclosure of Invention
The invention mainly aims to provide a dry gas sealing device free of isolation gas, and aims to solve the technical problem of complicated operation system caused by the fact that additional auxiliary equipment is required to be introduced into the existing dry gas sealing device to provide isolation gas.
In order to achieve the above purpose, the invention provides a dry gas sealing device free of isolation gas, which comprises a rotating shaft, a shaft sleeve and a sealing cylinder body, wherein the shaft sleeve is sleeved on the rotating shaft and is fixedly connected with the rotating shaft, a movable ring is fixedly installed on the shaft sleeve, the sealing cylinder body is rotatably installed on the rotating shaft, a static ring seat is arranged on the sealing cylinder body, a static ring is slidably installed on the static ring seat, the static ring is elastically connected with the bottom of the static ring seat through an elastic device, an auxiliary piece for blocking the static ring from sliding towards the bottom of the static ring seat is arranged at the bottom of the static ring seat, one end of the auxiliary piece is fixedly connected with the static ring seat, a gap exists between the other end of the auxiliary piece and the static ring, and the movable ring is tightly attached to the static ring.
Optionally, the elastic device is a main spring, the static ring is elastically connected with the bottom of the static ring seat through the main spring, the auxiliary piece is an auxiliary spring, and the stiffness of the auxiliary spring is greater than that of the main spring.
Optionally, the elastic device is a main spring, the static ring is elastically connected with the bottom of the static ring seat through the main spring, and the auxiliary piece is an auxiliary block.
Optionally, front end comb teeth and isolation teeth are respectively arranged at two ends of the sealing cylinder, and a gap range between an inner annular surface of the isolation teeth and the rotating shaft or the shaft sleeve is 0.15 mm-0.3 mm.
Optionally, keep apart the tooth and include keeping apart tooth clamp and carbocycle, the carbocycle is installed keep apart on the interior anchor ring of tooth clamp, the carbocycle with the pivot or the clearance scope of axle sleeve is 0.15mm ~0.2mm.
Optionally, a spring piece is arranged on the stationary ring, the main spring is contacted with the spring piece, and an annular groove is arranged at the position, corresponding to the auxiliary piece, on the spring piece.
Optionally, a gap adjusting piece is detachably mounted on the static ring seat, and the auxiliary piece is mounted on the gap adjusting piece.
Optionally, the distance between the auxiliary piece and the stationary ring is 4-7 μm.
Optionally, a sealing ring is arranged on a contact surface between the static ring seat and the inner side surface of the static ring.
Optionally, the moving ring is provided with a spiral groove on the outer side of the contact surface with the stationary ring.
The technical scheme adopted in the invention content has the following beneficial effects:
the invention relates to a dry gas sealing device free of isolation gas, which is supported by an elastic device and an auxiliary piece through a static ring. When the engine starts, the lower airflow pressure passes through the elastic device with lower static ring extrusion rigidity, and the larger airflow gap can be quickly opened, so that leakage airflow with enough flow rate can be provided and flows out to the downstream gear box through the static ring, and oil gas in the downstream gear box is prevented from reversely flowing into the sealing device. When the gap between the movable ring and the static ring linearly increases to a certain extent along with the pressure of the air flow, the static ring is contacted with the auxiliary piece, so that the linear increase of the leakage gap along with the pressure is restrained, the overlarge loss of leakage air flow is avoided, the leakage gap and the air flow leakage quantity of the movable and static rings in the process from the starting to the full load are ensured to be within a certain control range, meanwhile, the leakage air also has a certain flow velocity to flow to the downstream gear box, and the reverse series of oil gas in the downstream gear box is prevented from entering the sealing device. Therefore, the dry gas sealing device can isolate oil gas in the downstream gear box without using extra isolation gas or additionally configuring a compressed air source, thereby achieving the purposes of simplifying the structure of an operating system, reducing the power consumption of the system and improving the efficiency of the system.
Drawings
FIG. 1 is a schematic view of a conventional dry gas seal arrangement;
FIG. 2 is a schematic diagram of a dry gas seal device without isolation gas according to the present invention;
FIG. 3 is a schematic structural diagram of a dry gas seal device without isolation gas in embodiment 2 of the present invention;
FIG. 4 is an enlarged view of a portion of FIG. 2 or FIG. 3 at A;
FIG. 5 is a schematic structural diagram of a dry gas seal device without isolation gas in embodiment 3 of the present invention;
FIG. 6 is a partial enlarged view at B in FIG. 5;
FIG. 7 is a schematic diagram of the components of a compressed air source system that would be required if a conventional dry gas seal apparatus were to employ an additional isolation source;
FIG. 8 is a schematic diagram of the components of a conventional dry gas seal apparatus employing the necessary equipment system for extracting a flow of isolation gas from the main loop of the operating system.
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.
In the present invention, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In addition, if there is a description of "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.
The control of oil gas at the downstream of the dry gas sealing device is the core and key of the safe operation of an operating system. Because the core of the dry gas seal is a runner gap of a few micrometers between the dynamic and static rings, the factors which can influence the runner gap need to be controlled, wherein the very important control is the oil gas control in a gearbox downstream of the dry gas seal. Since the viscosity of the lubricating oil is much greater than that of the gas, the stirring of the seal against the liquid will generate a large amount of heat and thus cause the dry gas seal temperature to rise sharply, resulting in failure to form a stable gas film. Therefore, in the actual use process, a isolating air flow is required to be always introduced to separate from oil gas in the downstream gear box, so that the damage of the sealing surface caused by reverse oil gas flowing to the sealing surface is avoided.
Referring to fig. 1 (in the drawings, 1 is a rotating shaft, 2 is a shaft sleeve, 3 is a sealing cylinder, 4 is a front end comb tooth, 5 is a movable ring, 6 is a spiral groove, 7 is a stationary ring, 8 is a spring piece, 24 is a spring, 11 is a stationary ring seat, 12 is a separation tooth, 13 is a sealing ring body, air flow is injected from the side wall of the sealing cylinder 3 in use), fig. 1 is a schematic structure diagram of a conventional dry gas sealing device, in order to avoid excessive air leakage caused by too large distance between the movable ring 5 and the stationary ring 7, the spring 24 in the structure generally has large rigidity, the movable ring 5 and the stationary ring 7 can be separated to reach a critical distance at a relatively slow speed at the initial start-up stage and keep stable, in the process, the gap between the movable ring 5 and the stationary ring 7 is small, the air flow leaked to the downstream gear box direction of the system in the structure of the dry gas sealing device is small, the flow speed is low, the downstream reverse strings of the oil gas cannot be resisted, and the oil gas in the gear box in the operation system can easily enter the dry gas sealing device at this time to cause pollution. In order to avoid pollution caused by the fact that oil gas in a downstream gear box of the system enters the dry gas sealing device, isolation air flow needs to be additionally introduced into the rear end of the dry gas sealing device, part of the isolation air flow is mixed with leakage air flow to be mixed with leakage air flow and discharged, and part of the isolation air flow leaks to the downstream gear box at a certain flow speed, so that the oil gas in the gear box cannot enter the dry gas sealing device in a countercurrent mode, and pollution is avoided.
There are two sources of isolation air flow, one is low-pressure air flow generated by compressed air, and the other is working medium air flow after decompression is extracted from an operation system loop.
When the low-pressure air flow is used as the isolation air, referring to fig. 7, the air compressor 18, the buffer tank 19, the cold dryer 20, the flowmeter 21 and other devices are required to be configured in the loop, and finally the isolation air flow is generated for the dry air sealing device, if the air compressor is not required on site, the auxiliary device is particularly complicated by building a set of compressed air device for dry air sealing, the size and the weight of the device are far more than those of the dry air sealing device, and the economy and the compactness of the device are poor. In addition, when air is used as an isolation air source, air working medium is mixed in a downstream gear box under the zero leakage use scene of the supercritical carbon dioxide power generation system, and then the air working medium enters a main loop after circulation, so that the purity of carbon dioxide in the main loop is reduced, and the use requirement of the system cannot be met.
When working medium after air extraction and decompression in the main loop of the operation system is used as isolation air flow, referring to fig. 8, a decompression valve 22 needs to be configured to reduce high-pressure main loop air flow to dry gas sealing back pressure, meanwhile, a temperature regulator 23 needs to be configured to control the temperature to be 40-60 ℃ under the condition of throttling and decompression so as to ensure the safety of dry gas sealing and a downstream gear box, meanwhile, a flowmeter 21 needs to be arranged on the loop to monitor the flow, and finally, the isolation air flow is generated for the dry gas sealing device.
The two schemes adopting the isolation gas have two defects: firstly, complicated equipment needs to be configured, so that miniaturization design cannot be realized; secondly, the air flow in the main loop of the operation system is directly extracted, so that working medium of the main loop is lost, the working capacity is weakened, and the output power and the power generation efficiency of the system are reduced.
Based on the technical problems, the dry gas sealing device can effectively isolate oil gas of a downstream gear box under the working condition of starting up to full load operation on the premise of not introducing an external isolation air source.
Example 1
Referring to fig. 2 and 4, the invention provides a dry gas sealing device free of isolation gas, which comprises a rotating shaft 1, a shaft sleeve 2 and a sealing cylinder body 3, wherein the shaft sleeve 2 is sleeved on the rotating shaft 1 and is fixedly connected with the rotating shaft 1, a movable ring 5 is fixedly installed on the shaft sleeve 2, the sealing cylinder body 3 is rotatably installed on the rotating shaft 1, a static ring seat 11 is arranged on the sealing cylinder body 3, a static ring 7 is slidably installed on the static ring seat 11, the static ring 7 is elastically connected with the bottom of the static ring seat 11 through an elastic device, an auxiliary piece for blocking the static ring 7 from sliding towards the bottom of the static ring seat 11 is arranged at the bottom of the static ring seat 11, one end of the auxiliary piece is fixedly connected with the static ring seat 11, a gap exists between the other end of the auxiliary piece and the static ring 7, and the movable ring 5 and the static ring 7 are tightly adhered. The elastic structure in this embodiment is a main spring 9, the static ring 7 is elastically connected with the bottom of the static ring seat 11 through the main spring 9, the auxiliary member in this embodiment is an auxiliary spring 10, and the stiffness of the auxiliary spring 10 is greater than that of the main spring 9. The stiffness of the main spring 9 in this embodiment is smaller than the stiffness of the spring driving the stationary ring 7 in a typical dry gas sealing arrangement.
Referring to fig. 2 and 4, the front end comb teeth 4 and the isolation teeth 12 are respectively disposed at two ends of the sealing cylinder 3, and a gap between an inner ring surface of the isolation teeth 12 and the rotating shaft ranges from 0.15mm to 0.3mm. The dry gas sealing device can reduce the length requirements of the isolating teeth 12 and the front end comb teeth 4, so that the axial length of the rotating shaft can be reduced, the rigidity of the rotor and the critical rotation speed of the rotor are improved, and for a rigid rotor, the critical rotation speed isolating margin of the rotor can be improved, so that safer operation of equipment is ensured.
Referring to fig. 2 and 4, the stationary ring 7 is provided with a spring piece 8, the main spring 9 contacts with the spring piece 8, and an annular groove 17 is provided on the spring piece 8 corresponding to the auxiliary spring 10. The clearance adjusting piece 16 is detachably arranged on the static ring seat 11, the auxiliary spring 10 is arranged on the clearance adjusting piece 16, and the use requirement can be met by arranging annular grooves 17 with different depths or changing the clearance adjusting piece 16 with different thicknesses to control the interval between the auxiliary spring 10 and the spring piece 8 to be 4-7 mu m. The free length of the main spring 9 is 0.05mm-0.1mm longer than the free length of the auxiliary spring 10. A sealing ring 13 is arranged on the contact surface between the static ring seat 11 and the inner side surface of the static ring 7. The outside of the contact surface between the stationary ring 7 and the movable ring 5 is provided with a spiral groove 6, and the spiral groove 6 is used for generating dynamic pressure between the movable ring 5 and the stationary ring 7 when the stationary ring 7 rotates, so that the movable ring 5 and the stationary ring 7 are separated, and an air film is formed between the movable ring 5 and the stationary ring 7.
According to the specification of the dry gas seal design, when the air flow speed flowing into a downstream gear box can meet the requirement of more than 5m/s, the reverse flow of oil gas in the downstream gear box of the system to the sealing surfaces of the movable ring 5 and the stationary ring 7 of the dry gas seal can be avoided, and the leakage air flow speed of the dry gas seal can be controlled so as to directly replace the introduced isolation air flow. Because the mass flow of the leakage air flow is in direct proportion to the density, the flow speed and the flow area of the working medium, when the mass flow of the upstream leakage air flow is fixed, the flow speed of the working medium can be improved by controlling the pressure of the downstream working medium so as to limit the density of the working medium, and the effect of better isolating the downstream oil gas is achieved. In order to meet the above-mentioned gas flow rate requirement of 5m/s, the injection gas flow injected from the side wall of the seal cylinder 3 in this embodiment needs to be adjusted during use, considering the initial operating pressure P of the moving ring 5 and the stationary ring 7 in the dry gas seal device when opening s The highest operating pressure P of the movable ring 5 and the stationary ring 7 when being separated to the maximum distance is 3MPa to 6MPa e Is 18Mpa-25Mpa. Therefore, the dry gas sealing device operates at the highest operating pressure P e And an initial operating pressure P s In the dry gas sealing device, the elastic force of the movable ring 5 is changed due to the existence of a critical pressure point, namely the movable ring 5 is in contact with the auxiliary spring 10, wherein the critical pressure is as follows: kP s ×(n+1)/n-P e N, where k is the ratio of the maximum operating pressure to the leakage amount at the initial operating pressure, and can be selected to be 2-4 according to design requirements; n is the ratio of the stiffness of the auxiliary spring 10 to the stiffness of the main spring 9. Furthermore, the stiffness ratio n and the leakage ratio k have the following constraint relationship: [ (n+1) ×k-n]≥P e /P s . The air flow pressure of the downstream of the moving ring 5 and the static ring 7 is 0.1MPa (a) to 0.2MPa (a).
The invention relates to a dry gas sealing device free of isolation gas, which is supported by a stationary ring 7 through a main spring 9 and an auxiliary spring 10. When the engine starts, the main spring 9 with lower rigidity is extruded by the static ring 7 under lower airflow pressure, so that the opening of a larger airflow gap can be rapidly realized, and leakage airflow with enough flow rate can be provided to flow out to a downstream gear box through the dynamic ring 5 and the static ring 7, thereby avoiding oil gas in the downstream gear box from entering the sealing device. When the gap between the movable ring 5 and the static ring 7 linearly increases to a certain extent along with the pressure of the air flow, the static ring 7 is contacted with the auxiliary spring 10, so that the linear increase of the leakage gap along with the pressure is restrained, the overlarge leakage air flow loss is avoided, the leakage gap and the air flow leakage quantity of the movable ring 7 in the process from the start-up to the full load are ensured to be within a certain control range, meanwhile, the leakage air also has a certain flow velocity to flow to a downstream gear box, and the oil gas in the downstream gear box is prevented from entering the sealing device. Therefore, the dry gas sealing device can isolate oil gas in the downstream gear box without using extra isolation gas, so that an extra compressed air source is not needed to be configured, and the purposes of simplifying the system structure, reducing the power consumption of the system and improving the system efficiency are achieved. The invention can be used for scenes such as supercritical carbon dioxide zero leakage scenes.
Example 2
Referring to fig. 3 and 4, the invention provides a dry gas sealing device free of isolation gas, which comprises a rotating shaft 1, a shaft sleeve 2 and a sealing cylinder body 3, wherein the shaft sleeve 2 is sleeved on the rotating shaft 1 and is fixedly connected with the rotating shaft 1, a movable ring 5 is fixedly installed on the shaft sleeve 2, the sealing cylinder body 3 is rotatably installed on the rotating shaft 1, a static ring seat 11 is arranged on the sealing cylinder body 3, a static ring 7 is slidably installed on the static ring seat 11, the static ring 7 is elastically connected with the bottom of the static ring seat 11 through an elastic device, an auxiliary piece for blocking the static ring 7 from sliding towards the bottom of the static ring seat 11 is arranged at the bottom of the static ring seat 11, one end of the auxiliary piece is fixedly connected with the static ring seat 11, a gap exists between the other end of the auxiliary piece and the static ring 7, and the movable ring 5 and the static ring 7 are tightly adhered. The elastic structure in this embodiment is a main spring 9, the static ring 7 is elastically connected with the bottom of the static ring seat 11 through the main spring 9, the auxiliary member in this embodiment is an auxiliary spring 10, and the stiffness of the auxiliary spring 10 is greater than that of the main spring 9. The stiffness of the main spring 9 in this embodiment is smaller than the stiffness of the spring driving the stationary ring 7 in a typical dry gas sealing arrangement.
Referring to fig. 3 and 4, front comb teeth 4 and isolation teeth 12 are respectively disposed at two ends of the sealing cylinder 3. The dry gas sealing device can reduce the length requirements of the isolating teeth 12 and the front end comb teeth 4, so that the axial length of the rotating shaft can be reduced, the rigidity of the rotor and the critical rotation speed of the rotor are improved, and for a rigid rotor, the critical rotation speed isolating margin of the rotor can be improved, so that safer operation of equipment is ensured.
Referring to fig. 3 and 4, the isolating teeth 12 include an isolating tooth clamp 121 and a carbocycle 122, the carbocycle 122 is mounted on an inner ring surface of the isolating tooth clamp 121, when the sleeve 2 is shorter and is positioned in the sealing cylinder 3, the carbocycle 122 is close to the rotating shaft 1, and a gap between the carbocycle 122 and the sleeve 2 is 0.15 mm-0.2 mm; when the sleeve 2 is long and the end is located outside the sealing cylinder 3, the carbocycle 122 is close to the sleeve 2, and the gap between the carbocycle 122 and the sleeve 2 is 0.15 mm-0.2 mm, which is the case in this embodiment. Under the condition of the same mass flow rate, the flow rate of the air flow can be effectively improved by reducing the flow area of the air flow, and the radial clearance between the isolating teeth 12 and the shaft sleeve 2 is reduced. However, in the actual operation process, when the design clearance is too small, there may be a bump grinding between the static isolating teeth 12 and the rotating shaft sleeve 2, so that the isolating teeth 12 can be normally operated under the condition of the small design clearance, the isolating teeth 12 are modified to be designed into isolating tooth clamps 121 and carbocycles 122, and the carbocycles 122 can bear the bump grinding between the isolating teeth 12 and the shaft sleeve 2 without damage, which is also the key of the safe operation of the dry gas seal under the small design clearance, namely, the reason of smaller clearance in the embodiment.
The static ring 7 is provided with a spring piece 8, the main spring 9 is contacted with the spring piece 8, and an annular groove 17 is arranged at the position corresponding to the auxiliary spring 10 on the spring piece 8. The clearance adjusting piece 16 is detachably arranged on the static ring seat 11, the auxiliary spring 10 is arranged on the clearance adjusting piece 16, and the use requirement can be met by arranging annular grooves 17 with different depths or changing the clearance adjusting piece 16 with different thicknesses to control the interval between the auxiliary spring 10 and the spring piece 8 to be 4-7 mu m. The free length of the main spring 9 is 0.05mm-0.1mm longer than the free length of the auxiliary spring 10. A sealing ring 13 is arranged on the contact surface between the static ring seat 11 and the inner side surface of the static ring 7. The outside of the contact surface between the stationary ring 7 and the movable ring 5 is provided with a spiral groove 6, and the spiral groove 6 is used for generating dynamic pressure between the movable ring 5 and the stationary ring 7 when the stationary ring 7 rotates, so that the movable ring 5 and the stationary ring 7 are separated, and an air film is formed between the movable ring 5 and the stationary ring 7.
According to the specification of the dry gas seal design, when the air flow speed flowing into a downstream gear box can meet the requirement of more than 5m/s, the reverse flow of oil gas in the downstream gear box of the system to the sealing surfaces of the movable ring 5 and the stationary ring 7 of the dry gas seal can be avoided, and the leakage air flow speed of the dry gas seal can be controlled so as to directly replace the introduced isolation air flow. Because the mass flow of the leakage air flow is in direct proportion to the density, the flow speed and the flow area of the working medium, when the mass flow of the upstream leakage air flow is fixed, the flow speed of the working medium can be improved by controlling the pressure of the downstream working medium so as to limit the density of the working medium, and the effect of better isolating the downstream oil gas is achieved. In order to meet the above-mentioned gas flow rate requirement of 5m/s, the injection gas flow injected from the side wall of the sealing cylinder 3 in this embodiment needs to be adjusted during use, so that the initial operating pressures P of the movable ring 5 and the stationary ring 7 in the dry gas sealing device when opened s The highest operating pressure P of the moving ring 5 and the stationary ring 7 when separated to the maximum distance is 3MPa to 6MPa e Is 18Mpa-25Mpa. The dry gas sealing device is operated at the highest operating pressure P e And an initial operating pressure P s In the dry gas sealing device, the elastic force applied to the movable ring 5 is changed due to the existence of a critical pressure point, namely the movable ring 5 is in contact with the auxiliary spring 10, wherein the critical pressure is as follows: kP s ×(n+1)/n-P e N, where k is the ratio of the maximum operating pressure to the leakage amount at the initial operating pressure, and can be selected to be 2-4 according to design requirements; n is the ratio of the stiffness of the auxiliary spring 10 to the stiffness of the main spring 9. Furthermore, the stiffness ratio n and the leakage ratio k have the following constraint relationship: [ (n+1) ×k-n]≥P e /P s . The air flow pressure of the downstream of the moving ring 5 and the static ring 7 is 0.1MPa (a)0.2MPa(a)。
The invention relates to a dry gas sealing device free of isolation gas, which is supported by a stationary ring 7 through a main spring 9 and an auxiliary spring 10. When the engine starts, the main spring 9 with lower rigidity is extruded by the static ring 7 under lower airflow pressure, so that the opening of a larger airflow gap can be rapidly realized, and leakage airflow with enough flow rate can be provided to flow out to a downstream gear box through the dynamic ring 5 and the static ring 7, thereby avoiding oil gas in the downstream gear box from entering the sealing device. When the gap between the movable ring 5 and the static ring 7 linearly increases to a certain extent along with the pressure of the air flow, the static ring 7 is contacted with the auxiliary spring 10, so that the linear increase of the leakage gap along with the pressure is restrained, the overlarge leakage air flow loss is avoided, the leakage gap and the air flow leakage quantity of the movable ring 5 and the static ring 7 in the process from starting to full load are ensured to be within a certain control range, meanwhile, the leakage air also has a certain flow velocity to flow to a downstream gear box, and the oil gas in the downstream gear box is prevented from entering a sealing device. Therefore, the dry gas sealing device can isolate oil gas in the downstream gear box without using extra isolation gas, so that an extra compressed air source is not needed to be configured, and the purposes of simplifying the system structure, reducing the power consumption of the system and improving the system efficiency are achieved. The invention can be used for scenes such as supercritical carbon dioxide zero leakage scenes.
Example 3
Referring to fig. 5 and 6, the invention provides a dry gas sealing device free of isolation gas, which comprises a rotating shaft 1, a shaft sleeve 2 and a sealing cylinder body 3, wherein the shaft sleeve 2 is sleeved on the rotating shaft 1 and is fixedly connected with the rotating shaft 1, a movable ring 5 is fixedly installed on the shaft sleeve 2, the sealing cylinder body 3 is rotatably installed on the rotating shaft 1, a static ring seat 11 is arranged on the sealing cylinder body 3, a static ring 7 is slidably installed on the static ring seat 11, the static ring 7 is elastically connected with the bottom of the static ring seat 11 through an elastic device, an auxiliary piece for blocking the static ring 7 from sliding towards the bottom of the static ring seat 11 is arranged at the bottom of the static ring seat 11, one end of the auxiliary piece is fixedly connected with the static ring seat 11, a gap exists between the other end of the auxiliary piece and the static ring 7, and the movable ring 5 and the static ring 7 are tightly adhered. The elastic structure in this embodiment is a main spring 9, the static ring 7 is elastically connected with the bottom of the static ring seat 11 through the main spring 9, and the auxiliary member is an auxiliary block 15. The stiffness of the main spring 9 in this embodiment is smaller than the stiffness of the spring driving the stationary ring 7 in a typical dry gas sealing arrangement.
Referring to fig. 5 and 6, the front end comb teeth 4 and the isolation teeth 12 are respectively disposed at two ends of the sealing cylinder 3. The dry gas sealing device does not need isolation gas, so that the length requirements of the isolation teeth 12 and the front end comb teeth 4 can be reduced, the axial length of the rotating shaft 1 can be reduced, the rigidity of the rotor and the critical rotating speed of the rotor are improved, and for a rigid rotor, the critical rotating speed isolation margin of the rotor can be improved, so that safer operation of equipment is ensured.
Referring to fig. 5 and 6, the isolating teeth 12 include an isolating tooth clamp 121 and a carbocycle 122, the carbocycle 122 is mounted on an inner ring surface of the isolating tooth clamp 121, when the sleeve 2 is shorter and is positioned in the sealing cylinder 3, the carbocycle 122 is close to the rotating shaft 1, and a gap between the carbocycle 122 and the sleeve 2 ranges from 0.15mm to 0.2mm; when the sleeve 2 is long and the end is located outside the sealing cylinder 3, the carbocycle 122 is close to the sleeve 2, and the gap between the carbocycle 122 and the sleeve 2 is 0.15 mm-0.2 mm, which is the case in this embodiment. The reduction of the flow area through the sleeve can also effectively increase the flow velocity of the air flow under the condition of the same mass flow, and the radial clearance between the isolating teeth 12 and the sleeve 2 is reduced. However, in the actual operation process, when the design clearance is too small, there may be a bump grinding between the static isolating teeth 12 and the rotating shaft sleeve 2, so that the isolating teeth 12 are damaged, in order to ensure that the isolating teeth 12 can normally operate under the condition of the small design clearance, the isolating teeth 12 are modified to be designed into isolating tooth clamps 121 and carbocycles 122, and the carbocycles 122 can bear the bump grinding between the isolating teeth 12 and the shaft sleeve 2 without damage, which is also the key of the dry gas sealing safe operation under the condition of the small design clearance.
The static ring 7 is provided with a spring piece 8, the main spring 9 is contacted with the spring piece 8, and an annular groove 17 is arranged at the position, corresponding to the auxiliary block 15, of the spring piece 8. The clearance adjusting piece 16 is detachably arranged on the static ring seat 11, the auxiliary spring 10 is arranged on the clearance adjusting piece 16, and the use requirement can be met by arranging annular grooves 17 with different depths or changing the clearance adjusting piece 16 with different thicknesses to control the interval between the auxiliary block 15 and the spring piece 8 to be 4-7 mu m. A sealing ring 13 is arranged on the contact surface between the static ring seat 11 and the inner side surface of the static ring 7. The outside of the contact surface between the stationary ring 7 and the movable ring 5 is provided with a spiral groove 6, and the spiral groove 6 is used for generating dynamic pressure between the movable ring 5 and the stationary ring 7 when the stationary ring 7 rotates, so that the movable ring 5 and the stationary ring 7 are separated, and an air film is formed between the movable ring 5 and the stationary ring 7.
According to the specification of the dry gas seal design, when the air flow speed flowing into a downstream gear box can meet the requirement of more than 5m/s, the reverse flow of oil gas in the downstream gear box of the system to the sealing surfaces of the movable ring 5 and the stationary ring 7 of the dry gas seal can be avoided, and the leakage air flow speed of the dry gas seal can be controlled so as to directly replace the introduced isolation air flow. Because the mass flow of the leakage air flow is in direct proportion to the density, the flow speed and the flow area of the working medium, when the mass flow of the upstream leakage air flow is fixed, the flow speed of the working medium can be improved by controlling the pressure of the downstream working medium so as to limit the density of the working medium, and the effect of better isolating the downstream oil gas is achieved.
The invention relates to a dry gas sealing device free of isolation gas, which is supported by a stationary ring 7 through a main spring 9 and an auxiliary block 15. When the machine starts, air flow is injected from the side wall of the sealing cylinder body 3, the movable ring 5 rotates to generate pressure between the movable ring 5 and the static ring 7, the lower air flow pressure presses the main spring 9 with lower rigidity through the static ring 7, and the larger air flow gap opening can be rapidly realized, so that leakage air flow with enough flow rate is provided to flow out to a downstream gear box through the movable ring 5 and the static ring 7, and oil gas in the downstream gear box is prevented from entering the sealing device. When the gap between the movable ring 5 and the static ring 7 linearly increases to a certain extent along with the pressure of the air flow, the static ring 7 is contacted with the auxiliary block 15, so that the linear increase of the leakage gap along with the pressure is restrained, the overlarge leakage air flow loss is avoided, the leakage gap and the air flow leakage quantity of the movable ring 7 in the process from the start-up to the full load are ensured to be within a certain control range, meanwhile, the leakage air also has a certain flow velocity to flow to a downstream gear box, and the oil gas in the downstream gear box is prevented from entering the sealing device. Therefore, the dry gas sealing device can isolate oil gas in the downstream gear box without using extra isolation gas, so that an extra compressed air source is not needed to be configured, and the purposes of simplifying the system structure, reducing the power consumption of the system and improving the system efficiency are achieved. The invention can be used for scenes such as supercritical carbon dioxide zero leakage scenes.
The foregoing description is only of the preferred embodiments of the present application, and is not intended to limit the scope of the claims, and all equivalent structures or equivalent processes using the descriptions and drawings of the present application, or direct or indirect application in other related technical fields are included in the scope of the claims of the present application.
Claims (8)
1. A dry gas sealing device free of isolation gas is characterized in that: the sealing device comprises a rotating shaft, a shaft sleeve and a sealing cylinder body, wherein the shaft sleeve is sleeved on the rotating shaft, the shaft sleeve is fixedly connected with the rotating shaft, a movable ring is fixedly installed on the shaft sleeve, the sealing cylinder body is rotatably installed on the rotating shaft, a static ring seat is arranged on the sealing cylinder body, a static ring is slidably installed on the static ring seat, the static ring is elastically connected with the bottom of the static ring seat through a main spring, an auxiliary piece for blocking the static ring from sliding towards the bottom of the static ring seat is arranged at the bottom of the static ring seat, one end of the auxiliary piece is fixedly connected with the static ring seat, an interval exists between the other end of the auxiliary piece and the static ring, and the movable ring is tightly attached to the static ring;
the auxiliary piece is an auxiliary block or an auxiliary spring, and the rigidity of the auxiliary spring is larger than that of the main spring.
2. The isolation-free dry gas seal of claim 1, wherein: front end comb teeth and isolation teeth are respectively arranged at two ends of the sealing cylinder body, and the gap range between the inner annular surface of the isolation teeth and the rotating shaft or the shaft sleeve is 0.15 mm-0.3 mm.
3. The isolation-free dry gas seal of claim 2, wherein: keep apart the tooth including keeping apart tooth clamp and carbocycle, the carbocycle is installed keep apart on the interior anchor ring of tooth clamp, the carbocycle with the pivot or the clearance scope of axle sleeve is 0.15mm ~0.2mm.
4. The isolation-free dry gas seal of claim 1, wherein: the static ring is provided with a spring piece, the main spring is contacted with the spring piece, and an annular groove is arranged at the position, corresponding to the auxiliary piece, on the spring piece.
5. The isolation-free dry gas seal of claim 1, wherein: and the static ring seat is detachably provided with a gap adjusting piece, and the auxiliary piece is arranged on the gap adjusting piece.
6. The isolation-free dry gas seal of claim 1, wherein: the distance between the auxiliary piece and the stationary ring is 4-7 mu m.
7. The isolation-free dry gas seal of claim 1, wherein: and a sealing ring is arranged on the contact surface between the static ring seat and the inner side surface of the static ring.
8. The isolation-free dry gas seal of claim 1, wherein: the movable ring is provided with a spiral groove on the outer side of the contact surface with the stationary ring.
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