Gas working medium rotating shaft sealing device and gas working medium rotating machine
By designing the first and second sealing structures and the pressure relief alarm device on the rotating shaft of the gas working medium rotating machinery, the problem of difficulty in timely detecting micro-leaks in the rotating shaft sealing device is solved, and timely detection and alarm of gas leaks are achieved, which reduces the modification cost and reduces safety hazards.
Patent Information
- Application Number
- CN202422508288.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-17
- Publication Date
- 2025-09-23
- Estimated Expiration
- 2034-10-17
AI Technical Summary
It is difficult for existing rotary shaft sealing devices of gas working medium rotary machinery to detect micro leaks in time, which may lead to leakage of expensive or flammable and explosive gases, causing property losses and safety hazards.
A gas working medium rotating shaft sealing device is designed, which includes first and second sealing structures, a leakage channel and a pressure relief alarm device. Leakage is detected in time by monitoring the air pressure changes in the accommodation space, and an alarm or pressure relief is issued through a micro-pressure safety valve and a buzzer to achieve active pressure relief.
It realizes timely detection and alarm of gas leakage, reduces the labor intensity of manual detection, avoids safety hazards, reduces the modification cost of the rotating shaft sealing device, has strong adaptability, and can predict the replacement and repair needs of seals in advance.
Smart Images
Figure CN223375079U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of mechanical engineering, and in particular to a gas working medium rotary shaft sealing device and a gas working medium rotary machine. Background Art
[0002] In rotating machinery using gaseous working fluids, the exposed drive shafts (such as centrifugal compressors, screw compressors, vane compressors, scroll compressors, and Roots superchargers) or power take-off shafts (such as various positive displacement organic Rankine cycle expanders and natural gas turboexpanders) are the most vulnerable parts of the machinery to working fluid leakage. To prevent gaseous working fluid leakage, a sealing device is typically installed on the rotating shaft. Although various sealing methods for rotating shafts vary depending on the working fluid pressure, shaft speed, and working fluid type, including mechanical seals, dry gas seals, skeleton seals, skeleton-less lip and tooth seals, and filler seals, the methods vary.
[0003] by Figure 1 For example, in the gaseous working medium rotating machinery shown in the figure, when a small leak first develops in the rotating shaft seal (A), it's difficult to detect in time. It can only be detected when the leak becomes larger, such as by frequently applying soapy water daily or installing expensive working medium gas sensors. This can cause property damage when the working medium is relatively expensive, and poses a significant safety hazard when dealing with flammable and explosive working gases. Utility Model Content
[0004] The utility model provides a gas working medium rotating shaft sealing device, comprising: an end cover, used to cooperate with a working medium chamber to fix the rotating shaft and enable the rotating shaft to rotate along the axis; one end of the rotating shaft is arranged in the working medium chamber, and the other end extends outside the working medium chamber; a first sealing structure, arranged on a side of the end cover close to the working medium chamber, and is in sliding sealing contact with the outer peripheral surface of the rotating shaft; a second sealing structure, arranged on a side of the end cover away from the working medium chamber, and is in sliding sealing contact with the outer peripheral surface of the rotating shaft; the first sealing structure and the second sealing structure enclose a accommodating space in the end cover; the end cover is radially provided with a leakage channel, and the leakage channel extends into the accommodating space; a pressure relief alarm device, arranged on the leakage channel, is configured to actively relieve pressure and / or issue an alarm when the air pressure in the accommodating space is greater than a preset value.
[0005] In some embodiments, the second sealing structure includes a replaceable lip-tooth sealing ring; wherein the pressure value of the gas leakage resistance of the first sealing structure is greater than the pressure value of the gas leakage resistance of the second sealing structure.
[0006] In some embodiments, the pressure relief alarm device includes a micro-pressure safety valve, which is configured to release gas when the air pressure in the accommodation space is greater than a first preset pressure value, or to release gas manually; wherein the first preset pressure value is less than the gas leakage resistance pressure value of the second sealing structure.
[0007] In some embodiments, the alarm device includes a passive micro-pressure buzzer, which works when the air pressure in the accommodation space is greater than a second preset pressure value; wherein the second preset pressure value is less than the first preset pressure value.
[0008] In some embodiments, the alarm device comprises a pressure gauge.
[0009] In some embodiments, the end cover is further provided with an oil drain hole along the radial direction.
[0010] The present invention also provides a method for determining the working condition of a sealing structure, which is used to determine the working condition of the first sealing structure in the aforementioned gas working medium rotary shaft sealing device, comprising: step 1, calculating the amount of gas discharged during one opening and closing cycle of the micro-pressure safety valve, including:
[0011] The gas state equation PV=nRT is defined; wherein P represents the pressure in the accommodation space; V represents the volume of the accommodation space; n represents the molar amount of the working fluid gas in the accommodation space; R represents the gas constant; and T represents the temperature of the working fluid gas in the accommodation space.
[0012] Assuming that the working gas temperature remains unchanged, based on the gas state equation, the molar amount n of the working gas in the accommodation space at the moment the micro-pressure safety valve is opened is determined as: n = PV / RT;
[0013] Determine the molar amount n' of the working fluid gas in the accommodation space at the moment the micro-pressure safety valve is closed: n'=P'V / RT; wherein P' represents the pressure in the accommodation space at the moment the micro-pressure safety valve is closed, P>P' and n>n';
[0014] Step 2, calculate the gas leakage rate; assuming that the time of one opening and closing cycle of the micro-pressure safety valve is Δt, then the leakage rate = (nn ′ ) / Δt=VRT*(PP′) / Δt;
[0015] Step 3: When the leakage rate is greater than a leakage rate threshold, it is indicated that the first sealing structure needs to be repaired or replaced.
[0016] The utility model also provides a gas working medium rotating machine, comprising a rotating shaft, a working medium cavity and the aforementioned gas working medium rotating shaft sealing device, wherein the gas working medium rotating shaft sealing device is mechanically connected to the working medium cavity in a detachable manner; the rotating shaft passes through the end cover and is used to rotate driven by the gas working medium.
[0017] In some embodiments, the installation portion of the rotating shaft corresponding to the second sealing structure is at least quenched; the surface hardness of the installation portion is greater than 58HRC, and the surface roughness is not less than 0.8μm.
[0018] The technical solution of the utility model has at least the following beneficial effects:
[0019] (1) The structure is simple, the cost is low, and the implementation is convenient, and it can be directly modified on the existing equipment; (2) The gas leakage can be directly observed, and the alarm or pressure relief can be issued in time; thus, the safety hazards are avoided and the labor intensity of manual inspection is reduced; (3) The main sealing device of various rotating shafts is highly adaptable, and the sealing status can be predicted in advance, and whether the seal needs to be replaced or repaired can be determined at low cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.
[0021] Figure 1 It is a structural diagram of an existing gas working medium rotating machinery;
[0022] Figure 2 This is a schematic structural diagram of a gas working medium rotary shaft sealing device in a working state according to an embodiment of the present utility model;
[0023] Figure 3 This is a schematic cross-sectional view of the end cover of the gas working medium rotary shaft sealing device in an embodiment of the present utility model.
[0024] In the figure: A-rotating shaft sealing device; 1-bearing; 2-end cover O-ring; 3'-end cover; 4-first sealing structure; 5-sealing structure sleeve; 6'-leakage channel; 7'-second sealing structure; 8'-lip-tooth seal ring gland; 9-oil drain hole; 10-rotating shaft; 15-accommodation space; 16-auxiliary oil drain hole; 20-pressure relief alarm device; 11-micro-pressure safety valve; 12-passive micro-pressure buzzer; 13-fastening bolts; 14-pressure gauge. DETAILED DESCRIPTION
[0025] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.
[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.
[0027] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. In addition, the terms "first," "second," etc. are used only to distinguish the descriptions and are not to be understood as indicating or implying relative importance.
[0028] Example
[0029] refer to Figure 2 , Figure 2 This is a schematic diagram of the working state of the gas working medium rotary shaft sealing device provided by the utility model.
[0030] The gas working medium rotating machine may include a rotating shaft, a working medium cavity and a gas working medium rotating shaft sealing device, wherein the gas working medium rotating shaft sealing device is separably mechanically connected to the working medium cavity; the rotating shaft passes through the end cover and is used to rotate driven by the gas working medium.
[0031] In order to improve the sealing effect of the gas working medium rotary shaft sealing device and to be able to promptly detect the leakage of more expensive working medium gases (such as inert gases, etc.) and flammable and explosive working medium gases (such as hydrogen or oxygen, etc.), this specification provides a gas working medium rotary shaft sealing device, which includes a bearing 1, an end cover O-ring 2, an end cover 3', a first sealing structure 4, a sealing structure sleeve 5, a leakage channel 6', a second sealing structure 7', a lip-tooth seal ring pressure cover 8', an oil drain hole 9, a rotating shaft 10, an accommodating space 15, an auxiliary oil drain hole 16, a pressure relief alarm device 20, a micro-pressure safety valve 11, a passive micro-pressure buzzer 12, a fastening bolt 13 and a pressure gauge 14. It should be noted that, in order to save space, some process structures (such as the fastening bolt 13) and supporting structures (such as the lip-tooth seal ring pressure cover 8') will not be described in detail.
[0032] Combined with Figure 3The end cover 3' is used to cooperate with the working medium cavity to fix the rotating shaft 10 and enable the rotating shaft 10 to rotate along the axis; one end of the rotating shaft 10 is arranged in the working medium cavity, and the other end extends outside the working medium cavity.
[0033] The first sealing structure 4 is provided on the side of the end cover 3' close to the working medium cavity, and is in sliding sealing contact with the outer peripheral surface of the rotating shaft 10. The first sealing structure 4 can be implemented by adopting a variety of sealing technologies, such as mechanical sealing, dry gas sealing, skeleton sealing, etc., depending on the working medium pressure, shaft speed and working medium type. In some embodiments, the first sealing structure 4 can be Figure 1 The sealing device (A) of the rotating shaft 10 is consistent to achieve the same effect as that of the existing equipment (such as Figure 1 Direct modification on gas working medium rotating machinery).
[0034] The second sealing structure 7' is provided on the side of the end cover 3' away from the working medium chamber and is in sliding sealing contact with the outer peripheral surface of the rotating shaft 10. The second sealing structure 7' is used to provide an early warning when the main sealing device begins to leak slightly.
[0035] Since the purpose of the second sealing structure 7' is not to achieve secondary sealing, but to facilitate the observation of micro-leakage, in some embodiments, the second sealing structure 7' includes a replaceable lip-tooth seal. Specifically, the second sealing structure 7' can be a skeleton-less lip-tooth seal. The installation of the skeleton-less lip-tooth seal will not increase the rotational resistance of the rotating shaft 10 too much. Therefore, in some embodiments, its interference fit should be smaller. Accordingly, the pressure value of the first sealing structure 4 to resist gas leakage is greater than the pressure value of the second sealing structure 7' to resist gas leakage, such as the pressure value of the first sealing structure 4 to resist gas leakage is more than 10 times the pressure value of the second sealing structure 7' to resist gas leakage.
[0036] The first sealing structure 4 and the second sealing structure 7 ′ form an accommodating space 15 in the end cover 3 ′. The end cover 3 ′ is radially provided with a leakage channel 6 ′, which extends into the accommodating space 15 .
[0037] The pressure relief alarm device 20 is located on the leakage channel 6' and is configured to actively relieve pressure and / or sound an alarm when the pressure in the containment space 15 exceeds a preset value. The preset value may include a first preset pressure value and a second preset pressure value, etc., and can be determined in the machine manual and is not limited in this specification.
[0038] It should be noted that the volume of the leakage channel 6 ′ can be ignored, or it can be regarded as a part of the accommodating space 15 to facilitate subsequent calculations.
[0039] In some embodiments, the pressure relief alarm device 20 includes a micro-pressure safety valve 11 , which is configured to release gas when the pressure in the accommodating space 15 is greater than a first preset pressure value, or to release gas manually.
[0040] In some embodiments, the first preset pressure value is less than the gas leakage resistance pressure value of the second sealing structure 7' to avoid leakage of the second sealing structure 7' before pressure relief. Preferably, the gas leakage resistance pressure value of the second sealing structure 7' is at least twice the first preset pressure value.
[0041] In some embodiments, the micro-pressure safety valve 11 or the entire pressure relief alarm device 20 can be located away from the gas working medium rotating machinery to facilitate the direct discharge or recovery of toxic or flammable and explosive gases.
[0042] In some embodiments, the alarm device includes a passive micro-pressure buzzer 12. When the air pressure in the accommodation space 15 is greater than a second preset pressure value, the passive micro-pressure buzzer 12 works; the passive micro-pressure buzzer 12 does not require independent power supply and does not affect the pressure of the accommodation space 15, and is suitable for modification of existing gas working medium rotating machinery.
[0043] In some embodiments, the second preset pressure value is lower than the first preset pressure value, i.e., if the pressure in the accommodation space 15 is too high (greater than the second preset pressure value but less than the first preset pressure value), a buzzer sound and / or an alarm will be issued, and then, when the pressure further increases (exceeds the first preset pressure value), active pressure relief will be performed. In some embodiments, when the alarm is issued, an alarm command may also be sent simultaneously, so that other devices, such as light or electricity, can provide a reminder.
[0044] In some embodiments, the alarm device further includes a pressure gauge 14, which can be used to monitor the sealing condition and obtain actual pressure readings for subsequent calculations.
[0045] To reduce rotational resistance and extend the service life of the second sealing structure 7', a small amount of lubricating oil, not exceeding the centerline of the rotating shaft, may be placed in the accommodating space 15 to prevent heating of the sealing device. Alternatively, in some cases where a small amount of lubricating oil has passed through the first sealing structure 4, the end cover 3' may further include radially extending oil drain holes 9 for draining the lubricating oil. Furthermore, to facilitate manual draining of the lubricating oil from the leakage channel 6', in some embodiments, the end cover may also include radially extending auxiliary oil drain holes 16.
[0046] In some embodiments, the leakage channel 6' can also be used to periodically and proactively replenish lubricating oil to ensure the normal operation of the equipment.
[0047] In order to ensure the good operation of the gas working medium rotary machinery and reduce the influence of the second sealing structure 7', in some embodiments, the installation part of the rotating shaft 10 corresponding to the second sealing structure 7' is at least quenched; the surface hardness of the installation part is greater than 58HRC and the surface roughness is not less than 0.8μm.
[0048] Perfect seals don't exist in mechanical engineering. This gas-filled rotary shaft sealing device stores and monitors any leaks from the primary sealing structure within a containment space, enabling timely detection and discharge or recovery as needed. Its simple structure allows for easy retrofitting into existing equipment, reduces gas leakage losses, avoids safety hazards, and reduces the labor intensity of manual inspections.
[0049] This specification also provides a method for determining the working condition of a sealing structure, for determining the working condition of a first sealing structure. Specifically, the method includes:
[0050] Step 1: Calculate the amount of gas discharged during one opening and closing cycle of the micro-pressure safety valve, including:
[0051] Define the gas state equation PV = nRT; where P represents the pressure within the containment space; V represents the volume of the containment space; n represents the molar mass of the working gas within the containment space; R represents the gas constant; and T represents the working gas temperature within the containment space. The pressure within the containment space can be obtained using, for example, a pressure gauge; the volume of the containment space can be calculated from the design value of the device; and the gas constant can be directly obtained based on the actual working gas conditions.
[0052] Assuming that the working gas temperature (T) remains unchanged, based on the gas state equation, the molar amount n of the working gas in the accommodation space at the moment of opening of the micro-pressure safety valve is determined as: n = PV / RT;
[0053] Determine the molar amount n' of the working fluid gas in the accommodation space of the micro-pressure safety valve at the moment of closing: n'=P'V / RT; where P' represents the pressure in the accommodation space of the micro-pressure safety valve at the moment of closing, P>P' and n>n';
[0054] Step 2, calculate the gas leakage rate; assuming that the time of one opening and closing cycle of the micro-pressure safety valve is Δt, the leakage rate = (nn ′ ) / Δt=VRT*(PP′) / Δt; the unit of leakage rate is mol / s (mole per second).
[0055] Step 3: When the leakage rate is greater than the leakage rate threshold, it is indicated that the first sealing structure needs to be repaired or replaced. The leakage rate threshold can be specified before the gas working medium rotating machine according to the actual working environment or determined by manual inspection.
[0056] By using this judgment method, the first sealing structure can be monitored at low cost according to the state of the micro-pressure safety valve, and repaired or replaced in time to reduce losses.
[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.
Claims
1. A gas working medium rotating shaft sealing device, characterized in that: include: An end cover is used to cooperate with the working medium cavity to fix the rotating shaft and enable the rotating shaft to rotate along the axis; one end of the rotating shaft is arranged in the working medium cavity, and the other end extends outside the working medium cavity; a first sealing structure, provided on a side of the end cover close to the working medium chamber, and in slidable sealing contact with the outer peripheral surface of the rotating shaft; A second sealing structure is provided on a side of the end cover away from the working medium chamber and is in slidable sealing contact with the outer peripheral surface of the rotating shaft; The first sealing structure and the second sealing structure form an accommodation space within the end cover; the end cover is provided with a leakage channel in a radial direction, and the leakage channel extends into the accommodation space; The pressure relief alarm device is provided on the leakage channel and is configured to actively relieve pressure and / or sound an alarm when the air pressure in the accommodation space is greater than a preset value.
2. The gas working medium rotary shaft sealing device according to claim 1, characterized in that: The second sealing structure includes a replaceable lip-tooth sealing ring; Wherein, the pressure value of the gas leakage resistance of the first sealing structure is greater than the pressure value of the gas leakage resistance of the second sealing structure.
3. The gas working medium rotary shaft sealing device according to claim 1, characterized in that: The pressure relief alarm device includes a micro-pressure safety valve, which is configured to release gas when the air pressure in the accommodating space is greater than a first preset pressure value, or to release gas manually; The first preset pressure value is less than the gas leakage resistance pressure value of the second sealing structure.
4. The gas working medium rotary shaft sealing device according to claim 3, characterized in that: The alarm device includes a passive micro-pressure buzzer, which is activated when the air pressure in the accommodation space is greater than a second preset pressure value; The second preset pressure value is smaller than the first preset pressure value.
5. The gas working medium rotary shaft sealing device according to claim 3, characterized in that: The alarm device also includes a pressure gauge.
6. The gas working medium rotary shaft sealing device according to claim 1, characterized in that: The end cover is further provided with an oil drain hole along the radial direction.
7. A gas working medium rotary machine, characterized in that: It comprises a rotating shaft, a working medium cavity and a gas working medium rotating shaft sealing device as described in any one of claims 1 to 6, wherein the gas working medium rotating shaft sealing device is separably mechanically connected to the working medium cavity; the rotating shaft passes through the end cover and is used to rotate driven by the gas working medium.
8. The gas working medium rotary machine according to claim 7, characterized in that: The installation portion of the rotating shaft corresponding to the second sealing structure is at least quenched; the surface hardness of the installation portion is greater than 58HRC, and the surface roughness is not less than 0.8μm.