Secondary sealing device for nitrogen compressor

Abstract

The invention discloses a secondary sealing device for a nitrogen compressor. The secondary sealing device comprises an upper sealing sleeve, a lower crescent sealing cavity, a connecting bolt, a pipeline connector, a connecting pipeline, a one-way valve and an exhaust fan. The upper sealing sleeve is used for upper sealing outside four-stage sealing of the nitrogen compressor and attached to a shell of the nitrogen compressor. The lower crescent sealing cavity is used for lower sealing outside four-stage sealing of the nitrogen compressor, and a cavity for containing leaked gas is defined by the lower crescent sealing cavity; the connecting bolt is connected with the upper sealing sleeve and the lower crescent sealing cavity in a penetrating manner; the pipeline connector is arranged at the bottom of the lower crescent sealing cavity and communicates with a cavity body of the lower crescent sealing cavity. The other end of the connecting pipeline is connected with the inlet end of the one-way valve; the outlet end of the one-way valve communicates with the air inlet end of the exhaust fan. The device can be directly adapted to a narrow space of the shaft seal, can actively control and exhaust leaked gas, and is low in cost.

Description

Technical Field

[0001] This invention relates to the field of compressor sealing technology, and specifically to a secondary sealing device for a nitrogen compressor. Background Technology

[0002] Nitrogen compressors are key equipment used in industrial production for compressing and transporting nitrogen. Due to long-term exposure to high exhaust pressure, the fourth-stage sealing parts are prone to problems such as wear and erosion of the comb seals, resulting in slight nitrogen leakage. As the equipment operates for longer periods, the leakage will gradually increase.

[0003] Existing nitrogen compressors are mostly installed in relatively enclosed factory buildings. Leaking nitrogen cannot diffuse quickly, easily leading to a decrease in oxygen concentration within the factory and posing a safety hazard of nitrogen asphyxiation. To mitigate this problem, current technology typically uses a combination of natural ventilation and axial flow fans to replace air and maintain a stable oxygen concentration within the factory. However, this solution has significant drawbacks: 1. Safety hazards not completely eliminated: During equipment operation, local inspections and online testing are required. At this time, personnel need to approach the level 4 sealing parts. However, the axial flow fan can only achieve overall ventilation of the plant and cannot locally control and discharge the sealing leakage points. The leaked nitrogen may still accumulate in the inspection area, posing a risk of suffocation. 2. Insufficient reliability: If the axial flow fan malfunctions (such as motor damage or blade jamming) or is shut down for maintenance, the nitrogen level in the plant will quickly exceed the standard, and there is no backup control and exhaust method, which directly threatens the safe operation of the equipment. 3. Poor adaptability: The shaft seal space of the nitrogen compressor's fourth-stage seal is small, and existing general technologies such as reflux modification and integral sealing cover cannot be applied due to installation space limitations, making it difficult to solve leakage problems at the source.

[0004] In summary, existing technologies cannot simultaneously achieve sealing performance, safety and reliability, and cost control. There is an urgent need for a secondary sealing solution that can be directly adapted to the confined space of shaft seals, can actively control and discharge leaked gas, and is cost-effective. Summary of the Invention

[0005] In view of the fact that existing technologies cannot simultaneously achieve the sealing effect, safety and reliability, and cost control of nitrogen compressors, this invention provides a secondary sealing device for nitrogen compressors that can be directly adapted to the narrow space of shaft seals, can actively control and discharge leaked gas, and is inexpensive.

[0006] This invention discloses a secondary sealing device for a nitrogen compressor, comprising an upper sealing sleeve, a lower crescent-shaped sealing cavity, connecting bolts, a pipe joint, a connecting pipe, a one-way valve, and an exhaust fan; The upper sealing sleeve is used for upper sealing outside the fourth sealing of the nitrogen compressor and is attached to the shell of the nitrogen compressor; the lower crescent sealing cavity is used for lower sealing outside the fourth sealing of the nitrogen compressor and forms a cavity for containing leaked gas; the connecting bolt is arranged to connect the upper sealing sleeve and the lower crescent sealing cavity, so that the two are jointly arranged outside the fourth sealing of the nitrogen compressor and form a sealed space. The pipeline joint is arranged at the bottom of the lower crescent sealing cavity and is in communication with the cavity of the lower crescent sealing cavity; one end of the connecting pipeline is connected with the pipeline joint, and the other end is connected with the inlet end of the one-way valve; the outlet end of the one-way valve is in communication with the air inlet end of the exhaust fan, and the exhaust fan is used to provide power for exhausting the leaked gas.

[0007] As a further improvement of the application, the attached surface of the upper sealing sleeve and the shell is provided with a filler rubber layer, and the attached surface of the lower crescent sealing cavity and the shell is provided with a filler rubber layer.

[0008] As a further improvement of the application, a pipeline reducer is further arranged between the one-way valve and the exhaust fan, one end of the pipeline reducer is sealingly connected with the outlet end of the one-way valve, and the other end of the pipeline reducer is sealingly connected with the air inlet end of the exhaust fan, so as to adapt the interface size of the one-way valve and the exhaust fan.

[0009] As a further improvement of the application, an outlet reducer is further arranged at the air outlet end of the exhaust fan, and the small-diameter end of the outlet reducer is sealingly connected with the air outlet end of the exhaust fan, so as to expand the flow cross section of the exhaust gas and reduce the exhaust resistance.

[0010] As a further improvement of the application, the connecting bolt is made of stainless steel, and the number is 4-6, which are uniformly distributed on the connecting edge of the upper sealing sleeve and the lower crescent sealing cavity, so as to ensure that the attachment pressure between the two and the shell of the nitrogen compressor is uniform.

[0011] As a further improvement of the application, the opening pressure of the one-way valve is adapted to the leakage pressure of the fourth sealing of the nitrogen compressor, so as to ensure that the leaked nitrogen is unidirectionally exhausted and prevent external air or impurities from flowing back to the sealed space.

[0012] As a further improvement of the application, the exhaust fan is linked with the nitrogen compressor to start and stop.

[0013] Compared with the prior art, the application has the following beneficial effects: 1. Significant sealing and exhaust control effect: By sealing the leakage point through the sealed space and using a one-way valve and exhaust fan for directional exhaust, the oxygen concentration inside the plant can be stably maintained at a level basically consistent with the outdoor oxygen concentration, with no low oxygen alarm phenomenon, and the risk of nitrogen asphyxiation is completely eliminated. 2. High safety and reliability: The exhaust fan and compressor start and stop in tandem without manual intervention; and the one-way valve ensures that the gas is discharged in one direction, preventing the external airflow from flowing back. Even if the exhaust fan fails briefly, a small amount of leaked gas can still be temporarily stored in the sealed space, allowing time for troubleshooting. 3. High adaptability and low cost: The device has a compact overall structure, which is suitable for narrow shaft seal spaces and does not require modification of the compressor body; the manufacturing cost is low, and the installation and maintenance are simple, so it can be quickly promoted and applied. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the secondary sealing device for a nitrogen compressor disclosed in this invention.

[0015] In the picture: 1. Upper sealing sleeve, 2. Lower crescent-shaped sealing cavity, 3. Connecting bolts, 4. Pipe joint, 5. Connecting pipe, 6. Check valve, 7. Pipe reducer, 8. Outlet reducer, 9. Exhaust fan. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] The present invention will now be described in further detail with reference to the accompanying drawings: like Figure 1 As shown, this invention provides a secondary sealing device for a nitrogen compressor, comprising an upper sealing sleeve 1, a lower crescent-shaped sealing cavity 2, connecting bolts 3, a pipe joint 4, a connecting pipe 5, a one-way valve 6, a pipe reducer 7, an outlet reducer 8, and an exhaust fan 9; wherein, The upper sealing sleeve 1 of the present application is used for the upper sealing outside the fourth sealing of the nitrogen compressor, and is attached to the shell of the nitrogen compressor. The attached surface of the upper sealing sleeve 1 and the shell is provided with a filler rubber layer. The lower crescent sealing cavity 2 is used for the lower sealing outside the fourth sealing of the nitrogen compressor, and the lower crescent sealing cavity forms a cavity for containing leaked gas. The attached surface of the lower crescent sealing cavity 2 and the shell is provided with a filler rubber layer. The connecting bolt 3 is arranged to connect the upper sealing sleeve and the lower crescent sealing cavity, so that the two are jointly arranged outside the fourth sealing of the nitrogen compressor and form a sealed space. The pipeline joint 4 is arranged at the bottom of the lower crescent sealing cavity 2 and is in communication with the cavity of the lower crescent sealing cavity 2. One end of the connecting pipeline 5 is connected with the pipeline joint 4, and the other end is connected with the inlet end of the one-way valve 6. The outlet end of the one-way valve 6 is sealingly connected with the inlet end of the pipeline reducing piece 7. The outlet end of the pipeline reducing piece 7 is sealingly connected with the air inlet end of the exhaust fan 9, for adapting the interface size of the one-way valve 6 and the exhaust fan 9. The outlet reducing piece 8 is arranged at the air outlet end of the exhaust fan 9. The small-diameter end of the outlet reducing piece 8 is sealingly connected with the air outlet end of the exhaust fan 9, for expanding the flow cross section of the discharged gas and reducing the exhaust resistance.

[0018] Further, the connecting bolt 3 is made of stainless steel, and the number is 4-6, which are uniformly distributed on the connecting edge of the upper sealing sleeve 1 and the lower crescent sealing cavity 2, to ensure that the attaching pressure between the two and the shell of the nitrogen compressor is uniform.

[0019] Further, the opening pressure of the one-way valve 6 is adapted to the leakage pressure of the fourth sealing of the nitrogen compressor, to ensure that the leaked nitrogen is discharged in one direction and prevent the external air or impurities from flowing back to the sealing space.

[0020] Further, the exhaust fan 9 and the nitrogen compressor are linked to start and stop at the same time, that is, they are opened and closed at the same time. Embodiment

[0021] This embodiment is designed for a DN200 nitrogen compressor (fourth sealing exhaust pressure 12MPa) to design a secondary sealing device. The specific parameters are as follows: Upper sealing sleeve: 304 stainless steel material, thickness 8mm, arc radius matched with the compressor shell, and 15mm thick oil-resistant butyronitrile rubber filler rubber layer is arranged on the attached surface; Lower crescent sealing cavity: 304 stainless steel material, cavity volume 500cm³, 15mm thick oil-resistant butyronitrile rubber filler rubber layer is arranged on the attached surface; Connecting bolt: M12x30 stainless steel bolt, a total of 4, uniformly distributed on the connecting edge; Pipeline joint: DN15 stainless steel joint, welded at the bottom of the lower crescent sealing cavity; Connection pipeline: DN15 stainless steel pipe, length 1.8 m, both ends are connected by threaded sealing; One-way valve: DN15 stainless steel one-way valve, opening pressure 0.008 MPa; Pipeline reducing: DN15 to DN20 stainless steel reducing joint; Outlet reducing: DN20 to DN30 stainless steel reducing joint; Exhaust fan: power 50W axial exhaust fan, air volume 120m³ / h, linked with nitrogen compressor control loop.

[0022] The installation method of the secondary sealing device is: S1, pretreatment: clean the surface of the shell of the fourth sealing part of the nitrogen compressor, remove oil stains and rust, and ensure the flatness of the fitting surface; S2, sealing assembly installation: fit the lower crescent sealing cavity to the lower shell of the fourth sealing part, align and position, cover the upper sealing sleeve, pass through 4 connecting bolts and tighten them in turn (torque control is 25N·m), ensure that the filler rubber layer is in close contact with the shell without obvious gap; S3, exhaust assembly installation: connect the pipeline joint, connection pipeline, one-way valve, pipeline reducing, exhaust fan and outlet reducing in turn, wrap polytetrafluoroethylene sealing tape at each connection part to ensure no secondary leakage; S4, linkage debugging: connect the exhaust fan wire to the compressor control loop, test whether the exhaust fan starts synchronously when the compressor starts, and whether the one-way valve can normally open (verify by passing in 0.008 MPa compressed air).

[0023] After the effect verification device is installed, the nitrogen compressor is continuously operated for 30 days, and the following detection is carried out during this period: Oxygen concentration detection: use a portable oxygen concentration detector to detect at different positions in the plant (including the fourth sealing point detection area), and the oxygen concentration is always maintained at 20.8%-21.0%, without low oxygen alarm; Leakage detection: use soap solution method to detect the fitting surface of the sealing assembly and the shell, and the connection parts of the exhaust assembly, no bubbles are generated, confirming no secondary leakage; Reliability test: stop the exhaust fan for 30 minutes, the pressure in the sealed space is stable at 0.006 MPa (which does not exceed the opening pressure of the one-way valve), and the oxygen concentration in the plant does not decrease significantly, and the pressure quickly recovers to normal pressure after restarting the exhaust fan.

[0024] The advantages of the present application are: 1. Significant sealing and exhaust effect: by sealing the leakage point in the sealed space, and using one-way valve + exhaust fan for directional exhaust, the oxygen concentration in the plant can be stably maintained at the same level as the outdoor oxygen concentration, without low oxygen alarm phenomenon, and the risk of nitrogen asphyxiation is completely eliminated; 2. High safety and reliability: the exhaust fan is linked with the compressor to start and stop without manual intervention; and the one-way valve ensures one-way gas discharge to prevent external airflow backflow, even if the exhaust fan fails temporarily, the sealed space can still temporarily store a small amount of leaked gas, providing time for fault handling; 3. Strong adaptability and low cost: the overall structure of the device is compact, which is suitable for narrow space of shaft seal without modification of the compressor body; the manufacturing cost is low, and the installation and maintenance are simple, which can be quickly applied.

[0025] The above are only preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A secondary seal device for a nitrogen compressor, characterized by, The upper sealing sleeve is used for upper sealing outside the fourth sealing of the nitrogen compressor, and is attached to the shell of the nitrogen compressor. The upper sealing sleeve is used for upper sealing outside the fourth sealing of the nitrogen compressor, and is attached to the shell of the nitrogen compressor. The upper sealing sleeve and the shell are attached by a filler rubber layer.

2. The secondary seal device for a nitrogen compressor according to claim 1, characterized by The pipeline reducing is arranged between the one-way valve and the exhaust fan, one end of the pipeline reducing is sealingly connected with the outlet end of the one-way valve, and the other end of the pipeline reducing is sealingly connected with the air inlet end of the exhaust fan, so as to adapt the interface size of the one-way valve and the exhaust fan.

3. The secondary seal device for a nitrogen compressor according to claim 1, characterized by, The outlet reducing is arranged at the air outlet end of the exhaust fan, the small-diameter end of the outlet reducing is sealingly connected with the air outlet end of the exhaust fan, so as to expand the flow cross section of the exhaust gas and reduce the exhaust resistance.

4. The secondary seal device for a nitrogen compressor according to claim 3, characterized by The number of the connecting bolts is 4-6, which are evenly distributed on the connecting edges of the upper sealing sleeve and the lower crescent sealing cavity, so as to ensure that the attachment pressure between the upper sealing sleeve, the lower crescent sealing cavity and the shell of the nitrogen compressor is uniform.

5. The secondary seal device for a nitrogen compressor according to claim 1, characterized by The opening pressure of the one-way valve is adapted to the leakage pressure of the fourth sealing of the nitrogen compressor, so as to ensure that the leaked nitrogen is unidirectionally discharged and prevent external air or impurities from flowing back to the sealing space.

6. The secondary seal device for a nitrogen compressor according to claim 1, characterized by The exhaust fan is linked with the nitrogen compressor to start and stop together.

7. The secondary seal device for a nitrogen compressor according to claim 1, characterized by ​

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