Shaft seal device of low-pressure pump and low-pressure pump

Abstract

The utility model belongs to the technical field of natural gas transportation equipment, and discloses a shaft seal device of a low-pressure pump and the low-pressure pump. The shaft sealing device of the low-pressure pump comprises a pump shell, a pump shaft and a sealing assembly, the pump shell is provided with a connecting channel, and the inner wall of the connecting channel is provided with a step structure. The pump shaft is arranged in the inner cavity of the pump shell, penetrates through the connecting channel and is in transmission connection with the output end of the rotary driving mechanism. The sealing assembly comprises a plurality of first sealing washers, a plurality of second sealing washers and a sealing cover plate. The pump shaft is sleeved with the first sealing washers and the second sealing washers, and the first sealing washers and the second sealing washers are located in the connecting channel. The sealing cover plate is arranged on the pump shaft in a sleeving mode and detachably connected with the pump shell. Part of the sealing cover plate extends into the connecting channel so that the sealing cover plate can abut against the second sealing gasket on the uppermost portion. The elastic modulus of the first sealing washer is larger than that of the second sealing washer. The shaft sealing device of the low-pressure pump can fully seal the gap between the pump shell and the pump shaft, and the sealing effect on the low-pressure pump is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of natural gas transportation equipment technology, and in particular to a shaft sealing device for a low-pressure pump and a low-pressure pump. Background Technology

[0002] Natural gas is a clean energy source that can be used as fuel for heating. Natural gas is mostly stored in liquefied natural gas (LNG) tanks. These tanks are equipped with low-pressure pumps, the pump casing of which is connected to the tank's interior. The low-pressure pump pressurizes the LNG in the tank and delivers it to a high-pressure pump. The high-pressure pump then further pressurizes the LNG and sends it to a vaporizer for vaporization. The vaporized natural gas then enters pipelines for user consumption. A shaft seal is typically installed between the pump casing and shaft of the low-pressure pump to seal the gap between them, preventing LNG leaks that could lead to resource waste and environmental pollution.

[0003] In existing technologies, low-pressure pump shaft sealing devices typically use packing seals, which involve fitting multiple PTFE gaskets onto the pump shaft to fill the gap between the pump shaft and the pump casing. However, with this type of shaft sealing device, the PTFE gaskets will undergo plastic deformation under continuous pressure after long-term use, causing gaps to reappear between the pump shaft and the pump casing, reducing the sealing effect, and in severe cases, leading to natural gas leakage, resulting in resource waste and environmental pollution. Utility Model Content

[0004] The purpose of this utility model is to provide a shaft sealing device for a low-pressure pump and a low-pressure pump, which can fully seal the gap between the pump casing and the pump shaft, ensure the sealing effect of the low-pressure pump, and avoid resource waste and environmental pollution caused by natural gas leakage inside the low-pressure pump.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, a shaft sealing device for a low-pressure pump is provided, comprising:

[0007] The pump casing is provided with a connecting channel, and the inner wall of the connecting channel is provided with a stepped structure;

[0008] A pump shaft is disposed in the inner cavity of the pump housing, the pump shaft passes through the connecting channel, and the end of the pump shaft away from the pump housing is configured to be drively connected to the output end of the rotary drive mechanism;

[0009] The sealing assembly includes multiple first sealing gaskets, multiple second sealing gaskets, and a sealing cover plate. The multiple first sealing gaskets and multiple second sealing gaskets are all fitted onto the pump shaft and located within the connecting channel. The multiple first sealing gaskets are stacked vertically to form a sealing assembly. The multiple second sealing gaskets are vertically positioned on both sides of the sealing assembly. The lowest second sealing gasket abuts against the stepped structure. The sealing cover plate is fitted onto the pump shaft and is detachably connected to the pump housing. A portion of the sealing cover plate extends into the connecting channel to abut against the highest second sealing gasket. The elastic modulus of the first sealing gaskets is greater than that of the second sealing gaskets.

[0010] Optionally, a fitting structure is provided between two adjacent second sealing gaskets. The fitting structure includes a fitting protrusion and a fitting groove. One of the two adjacent second sealing gaskets is provided with the fitting protrusion, and the other is provided with the fitting groove. The fitting protrusion can be engaged in the fitting groove.

[0011] Optionally, the mating protrusion includes a serrated protrusion.

[0012] Optionally, the fitting protrusion includes a stepped protrusion.

[0013] Optionally, the shaft sealing device of the low-pressure pump further includes a connector and a fastener. The pump casing has a snap-fit ​​groove. The connector passes vertically through the sealing cover and is inserted into the snap-fit ​​groove. The fastener is sleeved on the end of the connector away from the pump casing and is threadedly connected to the connector. The lower end of the fastener abuts against the upper surface of the sealing cover.

[0014] Optionally, the connector includes a screw, and the fastener includes a nut.

[0015] Optionally, the first sealing gasket includes a graphite gasket.

[0016] Optionally, the second sealing gasket includes a PTFE gasket.

[0017] Secondly, a low-pressure pump is provided, including a pump body and a shaft sealing device of the low-pressure pump as described above, wherein the shaft sealing device of the low-pressure pump is disposed on the pump body.

[0018] The beneficial effects of this utility model are:

[0019] This utility model provides a shaft sealing device for a low-pressure pump and a low-pressure pump. The shaft sealing device includes a pump casing, a pump shaft, and a sealing assembly. When sealing the gap between the pump casing and the pump shaft, the pump shaft passes through the connecting channel of the pump casing and extends out of the pump casing. The extended part of the pump shaft is connected to a rotary drive mechanism. There is a gap between the inner wall of the connecting channel and the pump shaft. Multiple second sealing gaskets are divided into two groups, each group including multiple second sealing gaskets. First, the multiple second sealing gaskets of the first group are sequentially fitted onto the pump shaft. The lowermost second sealing gasket abuts against the stepped structure in the connecting channel. Then, multiple first sealing gaskets are sequentially fitted onto the pump shaft. Finally, the multiple second sealing gaskets of the second group are sequentially fitted onto the pump shaft. Finally, a sealing cover plate is fitted onto the pump shaft, and the sealing cover plate is moved vertically so that part of it extends into the connecting channel, connecting and fixing the pump casing and the sealing cover plate, so that the lower end of the sealing cover plate abuts against the uppermost second sealing gasket.

[0020] When the sealing cover plate presses against the uppermost second sealing gasket, the sealing cover plate applies vertical pressure to the first and second sealing gaskets. Since the elastic modulus of the first sealing gasket is greater than that of the second sealing gasket, the first sealing gasket will undergo radial elastic deformation under vertical pressure, thereby further sealing the gap between the connecting channel and the pump shaft. This can fully seal the gap between the pump casing and the pump shaft, ensuring the sealing effect of the low-pressure pump and avoiding resource waste and environmental pollution caused by natural gas leakage inside the low-pressure pump. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the shaft sealing device structure of the low-pressure pump provided in this embodiment of the utility model;

[0022] Figure 2 This is an enlarged view of point A in diagram 1.

[0023] In the picture:

[0024] 1. Pump casing;

[0025] 2. Pump shaft;

[0026] 3. Sealing assembly; 31. First sealing gasket; 32. Second sealing gasket; 33. Sealing cover;

[0027] 4. Interlocking structure;

[0028] 5. Connectors;

[0029] 6. Fasteners. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0031] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0032] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0033] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0034] Example 1

[0035] This embodiment provides a shaft sealing device for a low-pressure pump, such as... Figure 1 and Figure 2 As shown, it can fully seal the gap between the pump casing 1 and the pump shaft 2, prevent the shaft sealing device from failing due to long-term use, and avoid resource waste and environmental pollution caused by natural gas leakage.

[0036] like Figure 1 and Figure 2As shown, the shaft sealing device of the low-pressure pump includes a pump casing 1, a pump shaft 2, and a sealing assembly 3. The pump casing 1 has a connecting channel with a stepped structure on its inner wall. The pump shaft 2 is located within the inner cavity of the pump casing 1, passing through the connecting channel, and the end of the pump shaft 2 furthest from the pump casing 1 is configured to be connected to the output end of a rotary drive mechanism. An impeller is mounted on the pump shaft 2 within the inner cavity of the pump casing 1. When the low-pressure pump is running, the rotary drive mechanism rotates the pump shaft 2, which in turn drives the impeller, thereby transporting the liquefied natural gas (LNG) within the inner cavity of the pump casing 1 to the next processing equipment. The sealing assembly 3 includes multiple first sealing gaskets 31, multiple second sealing gaskets 32, and a sealing cover plate 33. The multiple first sealing gaskets 31 and multiple second sealing gaskets 32 are all fitted onto the pump shaft 2 and located within the connecting channel. The multiple first sealing gaskets 31 are stacked vertically to form a sealing assembly. Multiple second sealing gaskets 32 are vertically arranged on both sides of the sealing assembly, with the lowest second sealing gasket 32 ​​abutting against the stepped structure. A sealing cover plate 33 is fitted onto the pump shaft 2 and is detachably connected to the pump housing 1. A portion of the sealing cover plate 33 extends into the connecting channel to ensure tight contact between the sealing cover plate 33 and the highest second sealing gasket 32. The elastic modulus of the first sealing gasket 31 is greater than that of the second sealing gasket 32.

[0037] When sealing the gap between the pump casing 1 and the pump shaft 2 of the low-pressure pump, the pump shaft 2 passes through the connecting channel of the pump casing 1 and extends out of the pump casing 1. The extended part of the pump shaft 2 is connected to the rotary drive mechanism. There is a gap between the inner wall of the connecting channel and the pump shaft 2. The multiple second sealing gaskets 32 are divided into two groups, each group including multiple second sealing gaskets 32. First, the multiple second sealing gaskets 32 of the first group are sequentially fitted onto the pump shaft 2. The lowermost second sealing gasket 32 ​​abuts against the stepped structure in the connecting channel. Then, multiple first sealing gaskets 31 are sequentially fitted onto the pump shaft 2. The multiple second sealing gaskets 32 of the second group are sequentially fitted onto the pump shaft 2. Finally, the sealing cover plate 33 is fitted onto the pump shaft 2, and the sealing cover plate 33 is moved vertically so that part of it extends into the connecting channel, connecting and fixing the pump casing 1 and the sealing cover plate 33, so that the lower end of the sealing cover plate 33 abuts against the uppermost second sealing gasket 32. When the sealing cover plate 33 presses against the uppermost second sealing gasket 32, the sealing cover plate 33 will apply vertical pressure to the first sealing gasket 31 and the second sealing gasket 32. Since the elastic modulus of the first sealing gasket 31 is greater than that of the second sealing gasket 32, the first sealing gasket 31 will undergo radial elastic deformation under vertical pressure, thereby further sealing the gap between the connecting channel and the pump shaft 2. This can fully seal the gap between the pump casing 1 and the pump shaft 2, ensuring the sealing effect of the low-pressure pump and avoiding resource waste and environmental pollution caused by natural gas leakage inside the low-pressure pump.

[0038] In this embodiment, two first sealing gaskets 31 and four second sealing gaskets 32 are provided. The two first sealing gaskets 31 form a sealing assembly, and the four sealing gaskets are evenly distributed on the upper and lower sides of the sealing assembly. In other embodiments, more than two first sealing gaskets 31 and two to four or more second sealing gaskets 32 may be provided as needed, which is not limited here.

[0039] Optionally, such as Figure 1 and Figure 2 As shown, a fitting structure 4 is provided between two adjacent second sealing gaskets 32. The fitting structure 4 includes a fitting protrusion and a fitting groove. One of the two adjacent second sealing gaskets 32 is provided with a fitting protrusion, and the other is provided with a fitting groove. The fitting protrusion can be engaged in the fitting groove. By providing the fitting structure 4, the fitting protrusion is engaged in the fitting groove, which increases the contact area and friction between the two adjacent second sealing gaskets 32, thereby making them fit more tightly. This improves the sealing effect of the sealing assembly 3 on the gap between the pump housing 1 and the pump shaft 2, effectively preventing the leakage of liquefied natural gas in the inner cavity of the pump housing 1, and improving the reliability and durability of the seal. In addition, the two adjacent second sealing gaskets 32 are connected by the fitting protrusion and the fitting groove, which can prevent the second sealing gaskets 32 from shifting or falling off during use, increasing the connection strength between the two adjacent second sealing gaskets 32, making the sealing assembly 3 more stable as a whole, and improving the stability of the entire shaft sealing device.

[0040] In this embodiment, the fitting protrusion includes a serrated protrusion, and the corresponding fitting groove is set as a serrated groove. In other embodiments, the fitting protrusion may also be set as a stepped or other shaped protrusion, and the shape of the fitting groove may be set accordingly, which is not limited here.

[0041] Optionally, such as Figure 1 and Figure 2As shown, the shaft sealing device of the low-pressure pump also includes a connector 5 and a fastener 6. A snap-fit ​​groove is provided on the pump casing 1, and the connector 5 passes vertically through the sealing cover plate 33 and is installed in the snap-fit ​​groove. The fastener 6 is sleeved on the end of the connector 5 away from the pump casing 1 and is threadedly connected to the connector 5. The lower end of the fastener 6 abuts against the upper surface of the sealing cover plate 33. When part of the sealing cover plate 33 is inserted into the connecting channel and abuts against the uppermost second sealing gasket 32, the plug 5 is inserted vertically through the sealing cover plate 33 and into the snap-fit ​​groove until the lower end of the plug 5 abuts against the bottom of the snap-fit ​​groove. Then, the fastener 6 is fitted and threaded onto the plug 5 until the lower end of the fastener 6 abuts against the upper surface of the sealing cover plate 33. On the one hand, the sealing cover plate 33 can be connected and fixed, with a simple structure and easy operation. On the other hand, the sealing cover plate 33 can apply vertical pressure to the first sealing gasket 31 and the second sealing gasket 32, causing the first sealing gasket 31 to undergo radial elastic deformation under pressure, thereby fully sealing the gap between the pump shaft 2 and the pump housing 1 and improving the sealing effect.

[0042] For example, connector 5 includes a screw and fastener 6 includes a nut.

[0043] In this embodiment, the first sealing gasket 31 includes a graphite gasket, and the second sealing gasket 32 ​​includes a PTFE gasket. The PTFE gasket has good durability and can directly withstand the clamping pressure between the sealing cover plate 33 and the stepped structure, while the graphite gasket has good elastic properties and can produce radial elastic deformation when compressed, better sealing the gap between the pump shaft 2 and the pump housing 1. The combination of graphite and PTFE gaskets achieves complementary performance between the two types of gaskets, ensuring both sealing reliability and extending service life.

[0044] Example 2

[0045] This embodiment provides a low-pressure pump, including a pump body and a shaft sealing device as described above. The shaft sealing device is disposed on the pump body and can fully seal the pump body, preventing liquefied natural gas leakage from the pump body and avoiding resource waste.

[0046] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A shaft sealing device for a low-pressure pump, characterized in that, include: The pump casing (1) is provided with a connecting channel, and the inner wall of the connecting channel is provided with a stepped structure; A pump shaft (2) is disposed in the inner cavity of the pump housing (1). The pump shaft (2) passes through the connecting channel, and the end of the pump shaft (2) away from the pump housing (1) is configured to be connected to the output end of the rotary drive mechanism. The sealing assembly (3) includes multiple first sealing gaskets (31), multiple second sealing gaskets (32), and a sealing cover plate (33). The multiple first sealing gaskets (31) and multiple second sealing gaskets (32) are all sleeved on the pump shaft (2) and located in the connecting channel. The multiple first sealing gaskets (31) are stacked vertically to form a sealing assembly. The multiple second sealing gaskets (32) are vertically distributed on both sides of the sealing assembly. The lowermost second sealing gasket (32) abuts against the stepped structure. The sealing cover plate (33) is sleeved on the pump shaft (2). The sealing cover plate (33) is detachably connected to the pump housing (1). Part of the sealing cover plate (33) extends into the connecting channel so that the sealing cover plate (33) abuts against the uppermost second sealing gasket (32). The elastic modulus of the first sealing gasket (31) is greater than that of the second sealing gasket (32).

2. The shaft sealing device for a low-pressure pump according to claim 1, characterized in that, An interlocking structure (4) is provided between two adjacent second sealing gaskets (32). The interlocking structure (4) includes an interlocking protrusion and an interlocking groove. One of the two adjacent second sealing gaskets (32) is provided with the interlocking protrusion, and the other is provided with the interlocking groove. The interlocking protrusion can be engaged in the interlocking groove.

3. The shaft sealing device for a low-pressure pump according to claim 2, characterized in that, The interlocking protrusions include serrated protrusions.

4. The shaft sealing device for a low-pressure pump according to claim 2, characterized in that, The fitting protrusions include stepped protrusions.

5. The shaft sealing device for a low-pressure pump according to any one of claims 1-4, characterized in that, The shaft sealing device of the low-pressure pump also includes a plug (5) and a fastener (6). A snap-fit ​​groove is provided on the pump housing (1). The plug (5) passes vertically through the sealing cover plate (33) and is inserted into the snap-fit ​​groove. The fastener (6) is sleeved on the end of the plug (5) away from the pump housing (1) and is threadedly connected to the plug (5). The lower end of the fastener (6) abuts against the upper surface of the sealing cover plate (33).

6. The shaft sealing device for a low-pressure pump according to claim 5, characterized in that, The connector (5) includes a screw, and the fastener (6) includes a nut.

7. The shaft sealing device for a low-pressure pump according to any one of claims 1-4, characterized in that, The first sealing gasket (31) includes a graphite gasket.

8. The shaft sealing device for a low-pressure pump according to any one of claims 1-4, characterized in that, The second sealing gasket (32) includes a PTFE gasket.

9. A low-pressure pump, characterized in that, It includes a pump body and a shaft sealing device for a low-pressure pump as described in any one of claims 1-7, wherein the shaft sealing device for the low-pressure pump is disposed on the pump body.

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