Shaft sealing system, expander and refrigeration compressor

Abstract

The present application provides a shaft sealing system, an expander, and a refrigeration compressor, wherein the shaft sealing system includes a mechanical sealing module and an oil supply module; the mechanical sealing module is clamped in a bearing cavity between a rotating shaft and a fixed shell, and a sealing cavity is formed on the outside of the bearing cavity, and the sealing cavity is used for circulating the working medium; the oil supply module is connected to the bearing cavity to provide lubricating oil to the mechanical sealing module; the pressure in the sealing cavity is greater than the pressure in the bearing cavity; the expander and the refrigeration compressor include the above-mentioned shaft sealing system. The present application provides a shaft sealing system, an expander, and a refrigeration compressor, which solves the problem of lubricating oil leakage and contamination of the working medium side.

Description

Technical Field

[0001] The present application relates to the technical field related to organic Rankine cycle, and specifically to a shaft sealing system, an expander and a refrigeration compressor. Background Art

[0002] The Organic Rankine Cycle (ORC) is a closed cycle that typically uses organic working fluids such as pentafluoropropane R245fa, n-butane, isobutane, and R134a as circulating fluids. The expander is the core driving device in the ORC cycle, and the reliability of its shaft seal is crucial to the long-term stable operation of the circulation system.

[0003] At present, mechanical seals are the most commonly used shaft seal type for ORC expanders. Mechanical seals are installed on the expander's rotating shaft and consist of dynamic and static sealing end faces perpendicular to the rotating shaft. By providing lubricating oil to the dynamic and static sealing surfaces, they are kept in a fit state during relative sliding, thereby preventing the circulating organic working fluid from leaking to the outside (bearing side).

[0004] During the start-up, shutdown, and variable operating conditions of the ORC cycle, organic fluids often enter the lubricating oil system, and vice versa, lubricating oil enters the circulating fluid system, leading to contamination between the circulating fluid and the lubricating oil. When excessive organic fluids accumulate in the lubricating oil, on the one hand, the lubricating oil's quality deteriorates, affecting its effectiveness. On the other hand, the vaporization of organic fluids dissolved in the lubricating oil can cause unstable oil supply from the oil pump, shortening its service life and endangering the safe operation of the device. Once lubricating oil enters the organic fluid, it will spread throughout the entire system over extended periods of circulation. In particular, once the inner walls of the heat exchanger are coated with a layer of lubricating oil, the heat transfer effect and circulation efficiency will be significantly reduced, seriously impacting the economic efficiency of the equipment's operation. Summary of the Invention

[0005] The purpose of the present application is to provide a shaft sealing system, an expander and a refrigeration compressor, which solve the problem of lubricating oil leakage and contamination of the working medium side.

[0006] To achieve the above objectives, this application provides a technical solution:

[0007] A shaft sealing system, comprising a mechanical sealing module and an oil supply module;

[0008] The mechanical seal module is clamped in a bearing cavity between a rotating shaft and a fixed shell, and a sealing cavity is formed outside the bearing cavity, and the sealing cavity is used for circulating the working medium;

[0009] The oil supply module is connected to the bearing cavity and provides lubricating oil to the mechanical seal module;

[0010] The pressure in the sealing cavity is greater than the pressure in the bearing cavity.

[0011] In some embodiments of the present application, the shaft sealing system further includes a first pipeline, one end of which is connected to the bearing cavity at the location of the mechanical seal module, and the first pipeline discharges the lubricating oil from the bearing cavity;

[0012] A regulating valve is provided on the first pipeline, and the regulating valve regulates the pressure in the bearing cavity to be lower than the pressure in the sealing cavity.

[0013] In some embodiments of the present application, a first pressure sensor is provided in the sealed cavity, and the first pressure sensor monitors the pressure in the sealed cavity;

[0014] A second pressure sensor is provided in the first pipeline, and the second pressure sensor monitors the pressure in the first pipeline.

[0015] In some embodiments of the present application, the shaft sealing system further includes a second pipeline, both ends of which are connected to the oil supply module and the mechanical sealing module respectively, and the lubricating oil enters the mechanical sealing module from the oil supply module via the second pipeline.

[0016] In some embodiments of the present application, the shaft sealing system further includes an oil tank, the other end of the first pipeline is connected to the oil tank, and part of the leaked working fluid and lubricating oil enters the oil tank through the first pipeline.

[0017] In some embodiments of the present application, a heater is provided at the bottom of the oil tank, and the heater heats the working medium, so that the working medium vaporizes and rises to the top of the oil tank.

[0018] In some embodiments of the present application, a third temperature sensor is provided in the fuel tank, and the third temperature sensor monitors the temperature of the liquid in the fuel tank;

[0019] A liquid level monitor is provided in the oil tank, and the liquid level monitor monitors the liquid level in the oil tank;

[0020] A first temperature sensor is provided in the first pipeline, and the first temperature sensor monitors the temperature in the first pipeline;

[0021] A second temperature sensor is provided in the second pipeline, and the second temperature sensor monitors the temperature in the second pipeline.

[0022] In some embodiments of the present application, the shaft sealing system further includes an oil mist separator, a third pipeline, and a fourth pipeline, wherein the oil mist separator is provided with a filter element;

[0023] One end of the third pipeline is connected to the top of the oil tank, and the other end is connected to the input port of the oil mist separator;

[0024] One end of the fourth pipeline is connected to the output port at the bottom of the oil mist separator, and the other end is connected to the oil tank;

[0025] The working fluid and lubricating oil enter the oil mist separator from the top of the oil tank via the third pipeline, and the filter element absorbs and collects the lubricating oil, thereby separating the working fluid and lubricating oil.

[0026] In some embodiments of the present application, the shaft sealing system further includes a compressor, and the compressor is connected to the oil mist separator;

[0027] The compressor extracts the working medium from the oil mist separator.

[0028] In some embodiments of the present application, a third pressure sensor is provided at the top of the oil tank, and the third pressure sensor monitors the pressure at the top of the oil tank and transmits the top pressure data of the oil tank to the compressor, and the compressor operates at a variable frequency according to the top pressure data.

[0029] In some embodiments of the present application, the compressor is provided with a motor, and the motor controls the compressor.

[0030] In some embodiments of the present application, the shaft sealing system further includes a fifth pipeline, one end of the fifth pipeline being connected to a position of the bearing cavity away from the mechanical seal module, and the other end of the fifth pipeline being connected to the oil tank;

[0031] The working fluid and lubricating oil leaking from the sealing cavity to the bearing cavity enter the oil tank through the fifth pipeline.

[0032] In some embodiments of the present application, the air outlet of the compressor is connected to a low-pressure pipeline, and the compressor discharges the working fluid into the low-pressure pipeline, and then the working fluid flows back to the working fluid circulation system through the low-pressure pipeline.

[0033] In some embodiments of the present application, the oil tank is connected to the oil supply module, and the lubricating oil flows back from the oil tank to the oil supply module.

[0034] To achieve the above objectives, this application also provides a technical solution:

[0035] An expander comprises the above-mentioned shaft sealing system.

[0036] In some embodiments of the present application, the expander comprises an organic Rankine cycle expander;

[0037] Alternatively, the working fluid of the expander includes ammonia.

[0038] To achieve the above objectives, this application also provides a technical solution:

[0039] A refrigeration compressor comprises the above-mentioned shaft sealing system.

[0040] The beneficial effects of this application are:

[0041] 1. This application prevents the lubricating oil from invading the working medium side by controlling the pressure in the sealing chamber to be greater than the pressure in the bearing chamber, thereby solving the problem of lubricating oil contaminating the working medium circulation system.

[0042] 2. This application adjusts the regulating valve so that the pressure of the first pipeline is always lower than the pressure of the sealed chamber, thereby preventing the lubricating oil from leaking to the working medium side and solving the problem of lubricating oil contaminating the working medium circulation system.

[0043] 3. This application allows the working fluid to leak to the lubricating oil side, and the leaked working fluid will all enter the oil tank. Through the joint action of the heater at the bottom of the oil tank, the oil mist separator at the top of the oil tank, the compressor and other equipment, the working fluid leaked to the lubricating oil side can be completely separated and recovered and returned to the working fluid circulation system, avoiding the problem of the working fluid circulation system needing to regularly replenish the working fluid due to leakage at the shaft seal.

[0044] 4. The shaft seal system provided in this application is simple to operate and highly maneuverable, which can extend the maintenance period of the organic Rankine cycle generator set, reduce maintenance costs, and thus improve the economic benefits of the overall operation of the unit.

[0045] 5. This application is not only applicable to organic Rankine cycle expanders, but also to expanders using ammonia as the working fluid and various refrigeration compressors, and can solve the problem of lubricating oil contaminating the working fluid side and the working fluid circulation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 This is a schematic structural diagram of the shaft sealing system provided in Example 1 of the present application.

[0048] The main reference numerals in the drawings of this application specification are described as follows:

[0049] 1-Mechanical seal module; 2-Oil supply module; 3-Rotating shaft; 4-Stationary housing; 5-Bearing chamber; 6-Seal chamber; 7-First pipeline; 8-Regulating valve; 9-First pressure sensor; 10-Second pressure sensor; 11-Second pipeline; 12-First temperature sensor; 13-Second temperature sensor; 14-Oil tank; 15-Heater; 16-Third temperature sensor; 17-Liquid level monitor; 18-Oil mist separator; 19-Third pipeline; 20-Fourth pipeline; 21-Filter element; 22-Compressor; 23-Third pressure sensor; 24-Motor; 25-Fifth pipeline; 26-One-way valve. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of this application.

[0051] This application provides a shaft sealing system, an expander, and a refrigeration compressor, each of which is described in detail below. It should be noted that the order in which the following embodiments are described does not limit the preferred order of the embodiments of this application. Furthermore, the descriptions of each embodiment in the following embodiments each have their own emphasis. For details not described in one embodiment, please refer to the relevant descriptions of other embodiments.

[0052] Example 1

[0053] like Figure 1 As shown, in some embodiments of the present application, a shaft sealing system is provided, which includes a mechanical sealing module 1 and an oil supply module 2; the mechanical sealing module 1 is clamped in a bearing cavity 5 between a rotating shaft 3 and a fixed shell 4, and a sealing cavity 6 is formed on the outside of the bearing cavity 5, and the sealing cavity 6 is used for circulating a working medium; the oil supply module 2 is connected to the bearing cavity 5 to provide lubricating oil to the mechanical sealing module 1, and the working medium drives the rotating shaft 3 to rotate, and the mechanical sealing module 1 is arranged around the outer peripheral surface of the rotating shaft 3, and the rotating shaft 3 will contact the mechanical sealing module when rotating. Friction is generated by contact, and the lubricating oil can reduce frictional resistance; the pressure in the sealing chamber 6 is greater than the pressure in the bearing chamber 5, that is, there is a pressure gradient between the sealing chamber 6 and the bearing chamber 5, and the direction of the pressure gradient is from the sealing chamber 6 to the bearing chamber 5, which makes it possible for the lubricating oil located at the position of the mechanical sealing module 1 to not invade into the sealing chamber 6 against the direction of the pressure gradient. In this way, the present application solves the problem in the prior art that the lubricating oil will leak to the working fluid side and pollute the entire working fluid side circulation, and eliminates the phenomenon of the lubricating oil leaking to the working fluid side.

[0054] like Figure 1 As shown, in some embodiments of the present application, the shaft sealing system further includes a first pipeline 7, one end of which is connected to the bearing cavity 5 at the location of the mechanical seal module 1, and the first pipeline 7 discharges the lubricating oil. A regulating valve 8 is provided on the first pipeline 7, and the regulating valve 8 adjusts the pressure in the first pipeline 7 to be lower than the pressure in the sealing cavity 6. Under the action of the above-mentioned pressure gradient, the working medium in the sealing cavity 6 penetrates into the location of the mechanical seal module 1 and mixes with the lubricating oil. At this time, the working medium contaminates the lubricating oil. The present application provides the first pipeline 7 to divert the leaked working medium and the contaminated lubricating oil away from the location of the mechanical seal module 1, thereby ensuring the purity and quality of the lubricating oil at this location, and further ensuring the lubricating effect of the lubricating oil at this location.

[0055] like Figure 1 As shown, in some embodiments of the present application, a first pressure sensor 9 is provided in the first pipeline 7 to monitor the pressure in the first pipeline 7; a second pressure sensor 10 is provided in the sealed cavity 6 to monitor the pressure in the sealed cavity 6. By providing these two pressure sensors, the present application achieves monitoring of the pressure conditions in the sealed cavity 6 and the first pipeline 7, thereby enabling more accurate adjustment of the regulating valve 8 and facilitating better understanding and monitoring of the operation of the shaft sealing system by personnel.

[0056] like Figure 1 As shown, in some embodiments of the present application, the shaft sealing system also includes a second pipeline 11, the two ends of the second pipeline 11 are respectively connected to the oil supply module 2 and the mechanical sealing module 1, and the lubricating oil enters the mechanical sealing module 1 from the oil supply module 2 via the second pipeline 11.

[0057] like Figure 1 As shown, in some embodiments of the present application, the shaft sealing system further includes an oil tank 14, the other end of the first pipeline 7 is connected to the oil tank 14, and part of the leaked working fluid and lubricating oil enters the oil tank 14 through the first pipeline 7, and the oil tank 14 can store the above-mentioned leaked working fluid and contaminated lubricating oil.

[0058] like Figure 1As shown, in some embodiments of the present application, a heater 15 is provided at the bottom of the oil tank 14. The heater 15 heats the working fluid, which then vaporizes and rises to the top of the oil tank 14. The leaked working fluid enters the oil tank, and a portion of the working fluid and lubricating oil is liquefied through heat release and cooling and falls to the bottom of the oil tank 14. In some embodiments of the present application, because the specific gravity of the working fluid is greater than that of the lubricating oil, the liquefied working fluid will sink below the liquefied lubricating oil. The present application heats this portion of the working fluid that has sunk to the bottom by providing the heater 15 at the bottom of the oil tank 14, causing the working fluid to vaporize and rise to the top of the oil tank 14, thereby separating the vaporized working fluid from the liquefied lubricating oil.

[0059] like Figure 1 As shown, in some embodiments of the present application, a first temperature sensor 12 is provided in the first pipeline 7 to monitor the temperature in the first pipeline 7; a second temperature sensor 13 is provided in the second pipeline 11 to monitor the temperature in the second pipeline 11. By providing these two temperature sensors, the present application achieves monitoring of the temperature conditions in the first pipeline 7 and the second pipeline 11, which facilitates staff to better understand and monitor the operation of the shaft sealing system.

[0060] like Figure 1 As shown, in some embodiments of the present application, the oil tank 14 is provided with a third temperature sensor 16, and the third temperature sensor 16 monitors the temperature of the liquid in the oil tank 14. By providing the third temperature sensor 16, the present application realizes monitoring of the temperature condition in the oil tank 14, which facilitates the staff to better understand and monitor the overall operation of the oil tank 14 and the shaft sealing system.

[0061] like Figure 1 As shown, in some embodiments of the present application, a liquid level monitor 17 is provided in the oil tank 14, and the liquid level monitor 17 monitors the liquid level in the oil tank 14, so that the staff can better understand and monitor the overall operation of the oil tank 14 and the shaft sealing system.

[0062] like Figure 1As shown, in some embodiments of the present application, the shaft seal system further includes an oil mist separator 18, a third pipeline 19, and a fourth pipeline 20. The oil mist separator 18 is provided with a filter element 21. One end of the third pipeline 19 is connected to the top of the oil tank 14, and the other end is connected to the input port of the oil mist separator 18. One end of the fourth pipeline 20 is connected to the output port at the bottom of the oil mist separator 18, and the other end is connected to the oil tank 14. When the heater 15 heats the working medium, a small portion of the lubricating oil is vaporized. Therefore, the vaporized working medium and lubricating oil enter the oil mist separator 18 from the top of the oil tank 14 through the third pipeline 19. The filter element 21 absorbs and collects the lubricating oil, thereby separating the working medium and the lubricating oil. It is understood that in some embodiments of the present application, the filter element 21 has a selective absorption characteristic, that is, the filter element 21 can only absorb the lubricating oil and filter out the working medium.

[0063] like Figure 1 As shown, in some embodiments of the present application, the shaft sealing system further includes a compressor 22 , which is connected to the oil mist separator 18 ; the compressor 22 extracts the vaporized working medium in the oil mist separator 18 .

[0064] like Figure 1 As shown, in some embodiments of the present application, a third pressure sensor 23 is provided at the top of the oil tank 14. The third pressure sensor 23 monitors the pressure at the top of the oil tank 14 and transmits the top pressure data of the oil tank 14 to the compressor 22. The compressor 22 operates at a variable frequency according to the top pressure data.

[0065] like Figure 1 As shown, in some embodiments of the present application, the compressor 22 is provided with a motor 24 , and the motor 24 controls the compressor 22 .

[0066] like Figure 1 As shown, in some embodiments of the present application, the shaft sealing system also includes a fifth pipeline 25, one end of the fifth pipeline 25 is connected to the position of the bearing cavity 5 away from the mechanical seal module 1, and the other end is connected to the oil tank 14; when the compressor 22 extracts the working fluid in the oil mist separator 18, the top of the oil tank 14 will be in a negative pressure state, and because the pressure in the bearing cavity 5 is higher than the pressure in the oil tank 14, the working fluid and lubricating oil leaked from the sealing cavity 6 to the bearing cavity 5 can enter the oil tank 14 through the fifth pipeline 25, thereby ensuring the cleanliness of the bearing cavity 5.

[0067] In some embodiments of the present application, the air outlet of the compressor 22 is connected to a low-pressure pipeline (not shown), and the compressor 22 discharges the working fluid into the low-pressure pipeline, and then the working fluid flows back to the working fluid circulation system via the low-pressure pipeline, thereby realizing the recycling and reuse of the working fluid. The shaft seal system provided in the present application allows a portion of the working fluid to leak into the lubricating oil, and all the leaked working fluid enters the oil tank 14. Through the combined action of the heater 15, oil mist separator 18, compressor 22 and other equipment at the bottom of the oil tank 14, the working fluid leaked to the lubricating oil side can be completely separated and recovered and returned to the working fluid circulation system, avoiding the problem of the working fluid circulation system needing to regularly replenish the working fluid due to leakage at the shaft seal.

[0068] like Figure 1 As shown, in some embodiments of the present application, a one-way valve 26 is provided between the air outlet of the compressor 22 and the low-pressure pipeline, so as to facilitate the compressor 22 to discharge the working medium to the low-pressure pipeline and avoid the problem of the working medium flowing back at the air outlet of the compressor 22.

[0069] In some embodiments of the present application, the oil tank 14 is connected to the oil supply module 2, and the lubricating oil flows back from the oil tank 14 to the oil supply module 2, thereby realizing the recycling of the lubricating oil.

[0070] Example 2

[0071] An expander includes the shaft sealing system as described in Example 1, and the working fluid includes pentafluoropropane (R245fa). Other types of working fluids can also be selected according to actual needs.

[0072] In some embodiments of the present application, the expander includes an organic Rankine cycle expander; or, the working fluid of the expander includes ammonia.

[0073] Example 3

[0074] A refrigeration compressor includes the shaft sealing system described in Example 1.

[0075] The above is only a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims. In addition, the specification uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core ideas of the present application. The content of this specification should not be understood as limiting the present application.

Claims

1. A shaft sealing system, characterized in that: The shaft sealing system includes a mechanical sealing module and an oil supply module; The mechanical seal module is clamped in a bearing cavity between a rotating shaft and a fixed shell, and a sealing cavity is formed outside the bearing cavity, and the sealing cavity is used for circulating the working medium; The oil supply module is connected to the bearing cavity and provides lubricating oil to the mechanical seal module; The pressure in the sealing cavity is greater than the pressure in the bearing cavity; The shaft sealing system further includes a first pipeline, an oil tank, an oil mist separator, a third pipeline, a fourth pipeline and a compressor; One end of the first pipeline is connected to the bearing cavity at the location of the mechanical seal module, and the other end of the first pipeline is connected to the oil tank, so that part of the leaked working fluid and lubricating oil enters the oil tank through the first pipeline; A regulating valve is provided on the first pipeline, and the regulating valve regulates the pressure in the bearing cavity to be lower than the pressure in the sealing cavity; One end of the third pipeline is connected to the top of the oil tank, and the other end is connected to the input port of the oil mist separator; One end of the fourth pipeline is connected to the output port at the bottom of the oil mist separator, and the other end is connected to the oil tank; The working fluid and lubricating oil enter the oil mist separator from the top of the oil tank through the third pipeline, and then the working fluid and lubricating oil are separated; The compressor is connected to the oil mist separator, and the compressor extracts the working medium from the oil mist separator.

2. The shaft sealing system according to claim 1, characterized in that: A first pressure sensor is provided in the sealed cavity, and the first pressure sensor monitors the pressure in the sealed cavity; A second pressure sensor is provided in the first pipeline, and the second pressure sensor monitors the pressure in the first pipeline.

3. The shaft sealing system according to claim 2, characterized in that: The shaft sealing system further includes a second pipeline, both ends of which are connected to the oil supply module and the mechanical sealing module respectively, and the lubricating oil enters the mechanical sealing module from the oil supply module via the second pipeline.

4. The shaft sealing system according to claim 3, characterized in that: A heater is provided at the bottom of the oil tank, and the heater heats the working medium, so that the working medium vaporizes and rises to the top of the oil tank.

5. The shaft sealing system according to claim 3, characterized in that: A third temperature sensor is provided in the oil tank, and the third temperature sensor monitors the temperature of the liquid in the oil tank; A liquid level monitor is provided in the oil tank, and the liquid level monitor monitors the liquid level in the oil tank; A first temperature sensor is provided in the first pipeline, and the first temperature sensor monitors the temperature in the first pipeline; A second temperature sensor is provided in the second pipeline, and the second temperature sensor monitors the temperature in the second pipeline.

6. The shaft sealing system according to claim 4, characterized in that: The oil mist separator is provided with a filter element, which absorbs and collects the lubricating oil, thereby separating the working fluid and the lubricating oil.

7. The shaft sealing system according to claim 6, characterized in that: A third pressure sensor is provided at the top of the oil tank. The third pressure sensor monitors the pressure at the top of the oil tank and transmits the pressure data of the top of the oil tank to the compressor. The compressor operates at a variable frequency according to the pressure data.

8. The shaft sealing system according to claim 7, characterized in that: The compressor is provided with a motor, and the motor controls the compressor.

9. The shaft sealing system according to claim 6, characterized in that: The shaft sealing system further includes a fifth pipeline, one end of which is connected to a position of the bearing cavity away from the mechanical seal module, and the other end of which is connected to the oil tank; The working fluid and lubricating oil leaking from the sealing cavity to the bearing cavity enter the oil tank through the fifth pipeline.

10. The shaft sealing system according to any one of claims 7 to 9, characterized in that: The air outlet of the compressor is connected to a low-pressure pipeline. The compressor discharges the working medium into the low-pressure pipeline, and then the working medium flows back to the working medium circulation system through the low-pressure pipeline.

11. The shaft sealing system according to claim 10, characterized in that: The oil tank is connected to the oil supply module, and the lubricating oil flows back from the oil tank to the oil supply module.

12. An expander, characterized in that: The expander comprises the shaft sealing system according to any one of claims 1 to 11.

13. The expander according to claim 12, characterized in that The expander comprises an organic Rankine cycle expander; Alternatively, the working fluid of the expander includes ammonia.

14. A refrigeration compressor, characterized in that: The refrigeration compressor comprises a shaft sealing system according to any one of claims 1 to 11.

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