A double-cavity micro-positive pressure nitrogen sealing device for coal gas centrifugal compressor

Abstract

The utility model discloses a double-cavity micro-positive pressure nitrogen sealing device for a coal gas centrifugal compressor, which relates to the technical field of coal gas centrifugal compressors, including: a casing, an impeller is arranged in the casing, a main shaft is arranged through the casing, and the impeller is arranged on the main shaft; a first sealing device and a second sealing device are respectively arranged at both ends of the main shaft, and a first bearing seat and a second bearing seat are also respectively arranged at both ends of the main shaft; a baffle plate is respectively arranged on the main shaft on the side of the first sealing device and the second sealing device away from the casing; the first sealing device and the second sealing device are respectively provided with a graphite sealing sheet, and the side of the graphite sealing sheet close to the main shaft is set to a knife-shaped acute angle. The device reduces the contact area between the graphite sealing sheet and the main shaft, avoids local annealing due to high temperature, and causes oil leakage from the bearing seat. At the same time, the baffle plate prevents nitrogen from destroying the internal air pressure balance of the bearing seat, causing splashing of lubricating oil, thereby improving the safety and reliability of the device.

Description

Technical Field

[0001] The utility model relates to the technical field of coal gas centrifugal compressors, in particular to a double-cavity micro-positive pressure nitrogen sealing device for coal gas centrifugal compressors. Background Art

[0002] The gas centrifugal compressor is generally sealed by a double-cavity micro-positive pressure nitrogen sealing device to prevent gas leakage. Usually, when it is newly installed, the sealing condition is better. It only needs to ensure that the pressure is slightly higher than the gas pressure. The two nitrogen cavities form two radial nitrogen rings, which can cut off the gas and achieve zero gas leakage.

[0003] In the related technology, the circular graphite sealing sheet used in the current dual-cavity micro-positive pressure nitrogen sealing device is not consistent with the center of the main shaft. When the main shaft rotates at high speed, it rubs against the circular graphite sealing sheet, generating local high temperature, causing local annealing of the main shaft, and the temperature extends to the bearing seat, making the temperature of the bearing seat and the lubricating oil in the bearing seat too high, causing the bearing to be easily damaged and the life of the lubricating oil to be shortened; at the same time, the nitrogen in the sealing device is easy to leak from the front and rear ends, resulting in a waste of nitrogen, and when the nitrogen leaks from the bearing end, the nitrogen flows along the axial direction of the main shaft into the inside of the bearing seat, destroying the air pressure balance inside the bearing seat and causing the lubricating oil to splash. Utility Model Content

[0004] The utility model aims to provide a double-cavity micro-positive pressure nitrogen sealing device for a coal gas centrifugal compressor to solve at least one aspect of the problems and defects raised in the above-mentioned background technology.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A double-cavity slightly positive pressure nitrogen sealing device for a coal gas centrifugal compressor, comprising:

[0007] A casing, wherein an impeller is disposed in the casing, a main shaft is disposed through the casing, and the impeller is disposed on the main shaft;

[0008] A first sealing device and a second sealing device are respectively provided at both ends of the main shaft, and the first sealing device is connected with the second sealing device through a nitrogen pipe;

[0009] The two ends of the main shaft are respectively provided with a first bearing seat and a second bearing seat;

[0010] The first sealing device and the second sealing device are respectively provided with a baffle plate on the main shaft at a side away from the housing;

[0011] The first sealing device and the second sealing device are respectively provided with a graphite sealing sheet, and a side of the graphite sealing sheet close to the main shaft is set to a knife-edge-shaped acute angle.

[0012] The double-cavity micro-positive pressure nitrogen sealing device according to this solution has at least the following technical effects:

[0013] The double-cavity micro-positive pressure nitrogen sealing device for the coal gas centrifugal compressor is provided with graphite sealing sheets in the first sealing device and the second sealing device respectively, and the side of the graphite sealing sheet close to the main shaft is set to a knife-edge-shaped acute angle, which is different from the flat angle setting of the traditional graphite sealing sheet and is inconsistent with the center of the main shaft, resulting in high temperature due to friction between the main shaft and the graphite sealing sheet during rotation. The sealing device reduces the contact area between the graphite sealing sheet and the main shaft, thereby reducing the friction between the two and avoiding local annealing due to high temperature, so that the temperature of the main shaft extends to the bearing seat, causing oil leakage from the bearing seat, and causing a safety accident, thereby improving the safety and reliability of the device and extending the service life of the bearing seat.

[0014] At the same time, baffle plates are respectively provided on the main shafts of the first sealing device and the second sealing device away from the casing. When the nitrogen gas flows along the main shaft axis to the baffle plate, it is blocked, so that the nitrogen cannot enter the bearing seat, thereby preventing the nitrogen from destroying the air pressure balance inside the bearing seat and causing splashing of lubricating oil.

[0015] As a further solution of the utility model: a sealing ring is respectively provided at the connection between the first sealing device and one side of the housing and at the connection between the second sealing device and the other side of the housing.

[0016] By respectively arranging sealing rings at the connection between the first sealing device and one side of the casing and at the connection between the second sealing device and the other side of the casing, when the unit is running, the main shaft rotates at high speed, and nitrogen is blown into the air cavity at the same time, so that an air film is formed between the graphite sealing sheet and the main shaft. The buoyancy of the air film reduces the deviation between the graphite sealing sheet and the main shaft until they are basically concentric and achieve dynamic balance, thereby playing a sealing role.

[0017] As a further solution of the utility model: a nitrogen outlet is arranged on the top of the first sealing device, and a nitrogen inlet is arranged on the top of the second sealing device.

[0018] As a further solution of the utility model: an inlet regulating valve is provided on the nitrogen pipe on one side of the nitrogen inlet, an outlet regulating valve is provided on the nitrogen pipe on one side of the nitrogen outlet, and a flow regulating valve is provided on the nitrogen pipe at the bottom of the second sealing device.

[0019] Nitrogen enters the first sealing device through the nitrogen pipe from the nitrogen inlet of the second sealing device. When the graphite sealing sheet is slowly worn, coal gas will leak into the nitrogen. At this time, the pressure difference between the inlet and outlet of the sealing device needs to be adjusted through the inlet regulating valve, the outlet regulating valve and the flow regulating valve to make the sealing device achieve the best sealing effect and form a nitrogen gas ring that combines radial and axial directions, so that coal gas cannot penetrate the double-cavity nitrogen gas ring to ensure zero leakage of coal gas. Nitrogen flows out from the nitrogen outlet. If the residual pressure of nitrogen is sufficient, it can be introduced into the sealing device of other coal gas centrifugal fans, so that multiple sealing devices can achieve the sealing effect at the same time, and the nitrogen is circulated until the nitrogen pressure no longer plays a role in coal gas sealing, thereby reducing nitrogen consumption.

[0020] As a further solution of the utility model: pressure gauges are respectively provided on one side of the air inlet regulating valve, one side of the air outlet regulating valve and one side of the flow regulating valve.

[0021] The pressure gauge can provide accurate nitrogen pressure data and adjust the nitrogen pressure according to the coal gas pressure, so that the nitrogen pressure is always maintained slightly greater than the coal gas pressure. The two nitrogen cavities form two radial nitrogen gas rings, which play a role in cutting off the gas and keep the gas from leaking.

[0022] As a further solution of the utility model: the baffle plate includes a graphite packing, and two ends of the graphite packing are respectively provided with inclined surfaces, and the inclined surfaces at the two ends are coupled to form a ring shape.

[0023] Since the graphite packing is made of a soft material and is in the shape of a straight strip, the two ends of the graphite packing are provided with corresponding inclined surfaces, the graphite packing is bent, the inclined surfaces at the two ends are coupled to form a ring, and the ring is sleeved on the main shaft. The graphite packing, as a sealing material, has good sealing performance and can effectively block the nitrogen flow from flowing along the main shaft to the bearing seat, so that the nitrogen is stopped by the baffle plate to ensure that the nitrogen cannot enter the bearing seat.

[0024] As a further solution of the utility model: an upper shell and a lower shell are arranged outside the graphite packing, and the graphite packing is fixed on the main shaft through the upper shell and the lower shell.

[0025] By arranging an upper shell and a lower shell outside the graphite packing, the graphite packing is fixed on the main shaft through the upper shell and the lower shell, so that the annular graphite packing is more tightly connected to the main shaft, and the upper shell and the lower shell further increase the area of ​​the baffle plate, more effectively blocking nitrogen from entering the bearing seat, and the upper shell and the lower shell are detachable, which is convenient for replacing the graphite packing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to facilitate understanding by those skilled in the art, the present invention is further described below in conjunction with the accompanying drawings.

[0027] Figure 1 This is a schematic diagram of the structure of a double-cavity micro-positive pressure nitrogen sealing device for a coal gas centrifugal compressor;

[0028] Figure 2 It is a partial structural schematic diagram of a double-cavity micro-positive pressure nitrogen sealing device for a coal gas centrifugal compressor;

[0029] Figure 3 for Figure 2 A local enlarged view of point A;

[0030] Figure 4 It is a schematic diagram of the structure of graphite packing;

[0031] Figure 5 Schematic diagram of the structure of the baffle plate.

[0032] Reference numerals:

[0033] 101. Casing; 102. Impeller; 103. Main shaft; 104. First sealing device; 105. Second sealing device; 106. Nitrogen pipe; 107. First bearing seat; 108. Second bearing seat; 109. Baffle plate; 110. Graphite sealing sheet; 111. Sealing ring; 112. Nitrogen outlet; 113. Nitrogen inlet; 114. Inlet regulating valve; 115. Outlet regulating valve; 116. Flow regulating valve; 117. Pressure gauge; 118. Graphite packing; 119. Upper casing; 120. Lower casing. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0035] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] In the description of the present utility model, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0037] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0038] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model, that is, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the utility model provided in the accompanying drawings is not intended to limit the scope of the utility model claimed for protection, but merely represents selected embodiments of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0040] like Figure 1-5 The utility model embodiment shown is a double-cavity micro-positive pressure nitrogen sealing device for a gas centrifugal compressor, comprising: a casing 101, an impeller 102 is arranged in the casing 101, a main shaft 103 is arranged through the casing 101, and the impeller 102 is arranged on the main shaft 103; a first sealing device 104 and a second sealing device 105 are respectively arranged at both ends of the main shaft 103, and air cavities are respectively arranged in the first sealing device 104 and the second sealing device 105, and the first sealing device 104 and the second sealing device 105 are respectively provided with air cavities. The second sealing device 105 is connected through a nitrogen pipe 106; a first bearing seat 107 and a second bearing seat 108 are respectively provided at both ends of the main shaft 103; a baffle plate 109 is respectively provided on the main shaft 103 on the side of the first sealing device 104 and the second sealing device 105 away from the housing 101; the first sealing device 104 and the second sealing device 105 are respectively provided with a graphite sealing sheet 110, and the side of the graphite sealing sheet 110 close to the main shaft 103 is set to a knife-shaped acute angle.

[0041] Specifically, the coal gas centrifugal compressor uses a dual-cavity micro-positive pressure nitrogen sealing device, in which graphite sealing sheets 110 are respectively provided on the first sealing device 104 and the second sealing device 105, and the side of the graphite sealing sheet 110 close to the main shaft 103 is set to a knife-shaped acute angle, which is relative to the flat angle setting of the traditional graphite sealing sheet 110, and is inconsistent with the center of the main shaft 103, resulting in the main shaft 103 rubbing against the graphite sealing sheet 110 during rotation and generating high temperature. The sealing device reduces the contact area between the graphite sealing sheet 110 and the main shaft 103, reduces the friction between the two, avoids local annealing due to high temperature, so that the temperature of the main shaft 103 extends to the bearing seat, causing oil leakage from the bearing seat, and causing a safety accident, thereby improving the safety and reliability of the device and extending the service life of the bearing seat.

[0042] At the same time, baffle plates 109 are respectively provided on the main shaft 103 on the side of the first sealing device 104 and the second sealing device 105 away from the housing 101. When the nitrogen gas flows axially along the main shaft 103 to the baffle plate 109, it is blocked, so that the nitrogen cannot enter the interior of the bearing seat, thereby preventing the nitrogen from destroying the air pressure balance inside the bearing seat and causing splashing of the lubricating oil.

[0043] like Figure 1 and Figure 2 As shown, a sealing ring 111 is provided at the connection between the first sealing device 104 and one side of the housing 101 and at the connection between the second sealing device 105 and the other side of the housing 101 .

[0044] Specifically, sealing rings 111 are respectively provided at the connection between the first sealing device 104 and one side of the casing 101 and at the connection between the second sealing device 105 and the other side of the casing 101. When the unit is running, the main shaft 103 rotates at high speed, and nitrogen is blown into the air cavity at the same time, so that an air film is formed between the graphite sealing sheet 110 and the main shaft 103. The buoyancy of the air film reduces the deviation between the graphite sealing sheet 110 and the main shaft 103 until they are basically concentric and reach dynamic balance, thereby playing a sealing role.

[0045] like Figure 1 As shown, a nitrogen outlet 112 is provided at the top of the first sealing device 104, and a nitrogen inlet 113 is provided at the top of the second sealing device 105; an inlet regulating valve 114 is provided on the nitrogen pipe 106 on one side of the nitrogen inlet 113, an outlet regulating valve 115 is provided on the nitrogen pipe 106 on one side of the nitrogen outlet 112, and a flow regulating valve 116 is provided on the nitrogen pipe 106 at the bottom of the second sealing device 105.

[0046] Specifically, nitrogen enters the first sealing device 104 through the nitrogen pipe 106 from the nitrogen inlet 113 of the second sealing device 105. When the graphite sealing sheet 110 is slowly worn, the coal gas will leak into the nitrogen. At this time, the pressure difference between the inlet and outlet of the sealing device needs to be adjusted through the inlet regulating valve 114, the outlet regulating valve 115 and the flow regulating valve 116, so that the sealing device can achieve the best sealing effect, forming a nitrogen gas ring that combines radial and axial directions, so that the coal gas cannot penetrate the double-cavity nitrogen gas ring to ensure zero leakage of coal gas. Nitrogen flows out from the nitrogen outlet 112. If the residual pressure of nitrogen is sufficient, it can be introduced into the sealing device of other coal gas centrifugal fans, so that multiple sealing devices can achieve the sealing effect at the same time, and the nitrogen is circulated until the nitrogen pressure no longer plays a role in coal gas sealing, thereby achieving the effect of reducing nitrogen consumption.

[0047] like Figure 1 As shown, pressure gauges 117 are respectively provided on one side of the air inlet regulating valve 114 , one side of the air outlet regulating valve 115 , and one side of the flow regulating valve 116 .

[0048] Specifically, the pressure gauge 117 can provide accurate nitrogen pressure data, and adjust the nitrogen pressure by the pressure of the coal gas, so that the nitrogen pressure is always maintained slightly greater than the coal gas pressure. The two nitrogen cavities form two radial nitrogen gas rings, which play a role in cutting off the gas and keep the gas from leaking.

[0049] like Figure 4 and Figure 5 As shown, the baffle plate 109 includes a graphite packing 118, and two ends of the graphite packing 118 are respectively provided with inclined surfaces, and the inclined surfaces at the two ends are coupled to form a ring shape.

[0050] Specifically, since the graphite packing 118 is made of a soft material and is in the shape of a straight strip, the two ends of the graphite packing 118 are respectively provided with corresponding inclined surfaces, the graphite packing 118 is bent, the inclined surfaces at the two ends are coupled to form a ring, and the ring is sleeved on the main shaft 103. The graphite packing 118, as a sealing material, has good sealing performance and can effectively block the nitrogen gas flow from flowing along the axial direction of the main shaft 103 toward the bearing seat, so that the nitrogen is stopped by the baffle plate 109 to ensure that the nitrogen cannot enter the interior of the bearing seat.

[0051] like Figure 5 As shown, an upper shell 119 and a lower shell 120 are disposed outside the graphite packing 118 , and the graphite packing 118 is fixed on the main shaft 103 through the upper shell 119 and the lower shell 120 .

[0052] Specifically, an upper shell 119 and a lower shell 120 are provided outside the graphite packing 118, and the graphite packing 118 is fixed on the main shaft 103 through the upper shell 119 and the lower shell 120, so that the annular graphite packing 118 is more tightly connected to the main shaft 103, and the upper shell 119 and the lower shell 120 further increase the area of ​​the baffle plate 109, more effectively blocking nitrogen from entering the interior of the bearing seat, and the upper shell 119 and the lower shell 120 are detachable, which is convenient for replacing the graphite packing 118.

[0053] The above contents are merely examples and explanations of the structure of the utility model. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the utility model or exceed the scope defined in the claims, they should all fall within the protection scope of the utility model.

Claims

1. A double-cavity micro-positive pressure nitrogen sealing device for a coal gas centrifugal compressor, characterized in that: include: A casing (101), wherein an impeller (102) is disposed inside the casing (101), a main shaft (103) is disposed through the casing (101), and the impeller (102) is disposed on the main shaft (103); A first sealing device (104) and a second sealing device (105) are respectively provided at both ends of the main shaft (103), and the first sealing device (104) and the second sealing device (105) are connected via a nitrogen pipe (106); A first bearing seat (107) and a second bearing seat (108) are respectively provided at both ends of the main shaft (103); The first sealing device (104) and the second sealing device (105) are respectively provided with a baffle plate (109) on the main shaft (103) at a side away from the housing (101); The first sealing device (104) and the second sealing device (105) are respectively provided with a graphite sealing sheet (110), and a side of the graphite sealing sheet (110) close to the main shaft (103) is arranged to have a knife-edge-shaped acute angle.

2. The double-cavity slightly positive pressure nitrogen sealing device for a coal gas centrifugal compressor according to claim 1, characterized in that: A sealing ring (111) is provided at a connection point between the first sealing device (104) and one side of the housing (101), and at a connection point between the second sealing device (105) and the other side of the housing (101).

3. The double-cavity slightly positive pressure nitrogen sealing device for a coal gas centrifugal compressor according to claim 1, characterized in that: The top of the first sealing device (104) is provided with a nitrogen outlet (112), and the top of the second sealing device (105) is provided with a nitrogen inlet (113).

4. The double-cavity slightly positive pressure nitrogen sealing device for a coal gas centrifugal compressor according to claim 3 is characterized in that: An inlet regulating valve (114) is provided on the nitrogen pipe (106) on one side of the nitrogen inlet (113), an outlet regulating valve (115) is provided on the nitrogen pipe (106) on one side of the nitrogen outlet (112), and a flow regulating valve (116) is provided on the nitrogen pipe (106) at the bottom of the second sealing device (105).

5. The double-cavity slightly positive pressure nitrogen sealing device for a coal gas centrifugal compressor according to claim 4, characterized in that: Pressure gauges (117) are respectively provided on one side of the air inlet regulating valve (114), one side of the air outlet regulating valve (115), and one side of the flow regulating valve (116).

6. The double-cavity slightly positive pressure nitrogen sealing device for a coal gas centrifugal compressor according to claim 1, characterized in that: The baffle plate (109) comprises a graphite packing (118), and two ends of the graphite packing (118) are respectively provided with inclined surfaces, and the inclined surfaces at the two ends are coupled to form a ring shape.

7. The double-cavity slightly positive pressure nitrogen sealing device for a coal gas centrifugal compressor according to claim 6, characterized in that: An upper shell (119) and a lower shell (120) are arranged outside the graphite packing (118), and the graphite packing (118) is fixed on the main shaft (103) through the upper shell (119) and the lower shell (120).

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