Secondary oil seal sealing system of vertical double-screw pump

Abstract

The utility model discloses a secondary oil seal sealing system of a vertical double-screw pump, which belongs to the technical field of volume type screw pumps, the double-screw pump comprises a pump body, two screws which are meshed with each other and can rotate relatively are arranged in the pump body, a gear box used for driving the screws to rotate is arranged on the pump body on the side of a high-pressure cavity, and an oil seal is arranged on the gear box. A middle flange is arranged between the pump body and the gear box, the shaft end of the screw rod penetrates through the middle flange and extends into the gear box, the sealing system is arranged in the middle flange and comprises a first oil seal and a second oil seal which are sequentially arranged at the shaft end of the screw rod in a sleeving mode in the axial direction, and the first oil seal is close to the high-pressure cavity side; the medium is sealed, and a sealing area is formed in the high-pressure cavity; a lubricating ring is arranged in the middle flange between the first oil seal and the second oil seal and arranged at the shaft end of the screw in a sleeving mode. According to the utility model, the working requirement of gas-liquid mixed transportation can be met, and the reliability that a medium does not leak in the operation process of a pump set is improved through the structure of the two high-pressure oil seals.

Description

Technical Field

[0001] The utility model belongs to the technical field of positive displacement screw pumps, in particular to a vertical twin-screw pump secondary oil seal system. Background Art

[0002] As an efficient and reliable positive displacement fluid conveying device, the twin-screw pump is widely used in various industries, including the petroleum, chemical, and marine sectors, to transport a wide variety of media. A twin-screw pump consists of a driving screw and a driven screw, which mesh with each other and are mounted within the pump casing. The driving screw is driven by a prime mover (such as a motor or engine), while the driven screw is driven by the driving screw via synchronous gears. The two screws rotate in opposite directions, forming a series of sealed chambers. As the screw rotates, these chambers move axially, allowing the intake, sealing, and discharge of liquids. As the screws rotate, the meshing and squeezing action of the screws causes the pressure in the chamber near the intake end to be lower, forming a low-pressure chamber; while the pressure in the chamber near the discharge end to be higher, forming a high-pressure chamber.

[0003] Based on the user's specific requirements for product performance, weight, and dimensions, the twin-screw pump was ultimately selected as a vertical, single-suction twin-screw pump. Because the medium being transported contains gas, existing twin-screw pumps typically utilize an oil seal in the low-pressure chamber. Gas is highly permeable and can easily penetrate the seal, enter the pump body, or leak into the external environment. This not only reduces the pump's sealing performance but can also cause corrosion or contamination of the pump body. Furthermore, high gas content increases the risk of seal wear and failure. Summary of the Invention

[0004] In response to the problems existing in the prior art, the utility model provides a two-stage oil seal sealing system for a vertical twin-screw pump, which can meet the working requirements of gas-liquid mixed transportation. The structure of the two high-pressure oil seals improves the reliability of the pump group in preventing the medium from leaking during operation; and the sealing structure is simple and easy to operate, making it easy to observe whether the seal is leaking.

[0005] The utility model is implemented as follows: a vertical twin-screw pump double oil seal sealing system, the twin-screw pump includes a pump body, two screws that mesh with each other and can rotate relative to each other are arranged in the pump body, a gear box for driving the screws to rotate is arranged on the pump body located on the high-pressure chamber side, an intermediate flange is provided between the pump body and the gear box, the shaft ends of the screws pass through the intermediate flange and extend into the gear box, the sealing system is arranged in the intermediate flange, and includes a first oil seal and a second oil seal that are sequentially sleeved on the shaft ends of the screws in the axial direction, the first oil seal is close to the high-pressure chamber side, seals the medium and forms a sealing area in the high-pressure chamber;

[0006] A lubricating ring is provided in the middle flange between the first oil seal and the second oil seal, and the lubricating ring is sleeved on the end of the screw shaft.

[0007] Furthermore, the gearbox is provided with a notch on the side facing the intermediate flange. This notch and the upper end surface of the intermediate flange enclose a lubrication chamber. A constant-position oil cup, connected to the lubrication chamber, is provided on the gearbox on the side of the lubrication chamber. This constant-position oil cup provides supplemental lubrication for the first and second oil seals. The constant-position oil cup replenishes the oil level in the lubrication chamber, thereby providing supplemental lubrication for the first and second oil seals. Furthermore, the oil gauge level in the constant-position oil cup is observed to determine whether media leakage has occurred, providing direct feedback on the operating status of the first and second oil seals.

[0008] Furthermore, a vent pipe connected to the lubrication chamber is provided on the gear box located on one side of the lubrication chamber. The vent pipe can ensure pressure balance in the lubrication chamber.

[0009] Furthermore, a discharge valve connected to the lubrication chamber is provided on the gear box located on one side of the lubrication chamber. Once a small amount of medium leaks from the discharge valve, the medium can be discharged through the discharge valve.

[0010] Furthermore, a third oil seal is provided in the gear box at a position where the screw shaft end passes through, and the third oil seal sleeve is provided at the screw shaft end.

[0011] Furthermore, sealing rings are provided on the contact end surfaces between the pump body, the intermediate flange and the gear box.

[0012] Furthermore, a mounting blind hole is provided in the intermediate flange at the position where the axial end of the screw passes through, and the first oil seal, the second oil seal and the lubricating ring are all provided in the mounting blind hole.

[0013] Furthermore, the first oil seal and the second oil seal are high-pressure oil seals, capable of withstanding a pressure of ≯2.5 MPa.

[0014] Furthermore, the shaft section in contact with the first and second oil seals is hardened to form a hardened section, thereby ensuring the reliability of the operation of the first and second oil seals.

[0015] The utility model has the following advantages and technical effects: due to the adoption of the above technical scheme, it can meet the working requirements of gas-liquid mixed transportation, and the structure of the two high-pressure oil seals improves the reliability of the pump group in preventing the medium from leaking during operation; and the sealing structure is simple and easy to operate, and it is easy to observe whether the seal is leaking.

[0016] The first oil seal is directly connected to the high-pressure chamber to seal the medium. The second oil seal not only serves as a safety device in case the first oil seal fails, but also can seal the lubricating oil, ensuring the physical isolation between the medium and the lubricating oil; the lubricating ring ensures the lubrication of the first and second oil seals, ensuring that the oil seals do not run dry when conveying media containing gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the entire structure provided by an embodiment of the utility model;

[0018] Figure 2 It is a schematic AA cross-sectional view provided by an embodiment of the present utility model.

[0019] In the figure: 1. Pump body; 1-1. Sealing area; 2. Screw; 3. Gearbox; 4. Intermediate flange; 5. First oil seal; 6. Second oil seal; 7. Lubrication ring; 8. Lubrication chamber; 9. Constant level oil cup; 10. Breather pipe; 11. Third oil seal; 12. Sealing ring; 13. Drain valve. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] It should be noted that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicating directions or positional relationships, are based on the directions 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 direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0022] like Figure 1 and Figure 2 As shown, the present application provides a vertical twin-screw 2-pump double oil seal sealing system, the twin-screw 2-pump includes a pump body 1, in which two screws 2 that are meshed with each other and can rotate relative to each other are arranged, and a gear box 3 for driving the screw 2 to rotate is provided on the pump body 1 located on the high-pressure chamber side.

[0023] An intermediate flange 4 is provided between the pump body 1 and the gear box 3. The axial end of the screw 2 passes through the intermediate flange 4 and extends into the gear box 3. The sealing system is arranged in the intermediate flange 4, including a first oil seal 5 and a second oil seal 6 which are sequentially sleeved on the axial ends of the screw 2 along the axial direction. The first oil seal 5 is close to the high-pressure chamber side to seal the medium and form a sealing area 1-1 in the high-pressure chamber.

[0024] A lubricating ring 7 is provided in the middle flange 4 between the first oil seal 5 and the second oil seal 6 , and the lubricating ring 7 is sleeved on the axial end of the screw 2 .

[0025] Specifically, a mounting blind hole is provided in the middle flange 4 at the position where the axial end of the screw 2 passes through, and the first oil seal 5 , the second oil seal 6 and the lubricating ring 7 are all provided in the mounting blind hole.

[0026] Specifically, the first and second oil seals 5 and 6 are high-pressure WCP21 seals capable of withstanding pressures ≤ 2.5 MPa. The shaft sections contacting the first and second oil seals 5 and 6 are hardened to form hardened sections, ensuring reliable operation of the first and second oil seals 5 and 6.

[0027] Furthermore, the gearbox 3 is provided with a notch on the side facing the intermediate flange 4. The notch and the upper end surface of the intermediate flange 4 enclose a lubrication chamber 8. A constant-level oil cup 9 is provided on the gearbox 3 on the side facing the lubrication chamber 8, communicating with the lubrication chamber 8. The constant-level oil cup 9 provides back-up lubrication for the first and second oil seals 5 and 6. The constant-level oil cup 9 replenishes the oil level in the lubrication chamber. Lubricating oil in the lubrication chamber passes through the mounting blind hole to provide back-up lubrication for the first and second oil seals 5 and 6. Furthermore, the oil level in the constant-level oil cup 9 is used to determine whether medium leakage has occurred, providing direct feedback on the operating status of the first and second oil seals 5 and 6. Preferably, a vent pipe 10 is provided on the gearbox 3 on the side facing the lubrication chamber 8, communicating with the lubrication chamber 8. The vent pipe 10 ensures pressure balance in the lubrication chamber 8. Preferably, a drain valve 13 is provided on the gearbox 3 on the side facing the lubrication chamber 8, communicating with the lubrication chamber 8. Once a small amount of medium leakage occurs through the provided discharge valve 13 , the medium can be discharged through the discharge valve 13 .

[0028] Furthermore, a third oil seal 11 is provided in the gear box 3 at a position where the axial end of the screw 2 passes through, and the third oil seal 11 is sleeved on the axial end of the screw 2 .

[0029] Furthermore, the contact end surfaces between the pump body 1, the intermediate flange 4 and the gear box 3 are all provided with sealing rings 12. Specifically, the sealing ring 12 is an O-type sealing ring 12.

[0030] The adoption of the above technical solution can meet the working requirements of gas-liquid mixed transportation. The structure of the two high-pressure oil seals improves the reliability of the pump group in preventing the medium from leaking during operation. In addition, the sealing structure is simple and easy to operate, making it easy to observe whether the seal is leaking.

[0031] The first oil seal 5 is directly connected to the high-pressure chamber to seal the medium. The second oil seal 6 not only serves as a safety device in case the first oil seal 5 fails, but also can seal the lubricating oil, ensuring the physical isolation between the medium and the lubricating oil; the lubricating ring 7 ensures the lubrication of the first oil seal 5 and the second oil seal 6, ensuring that the oil seals do not run dry when conveying a medium containing gas.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A vertical twin-screw pump double oil seal system, the twin-screw pump includes a pump body, wherein two screws are provided in the pump body and are meshed with each other and can rotate relative to each other, and a gear box for driving the screws to rotate is provided on the pump body located on the high-pressure chamber side, characterized in that: An intermediate flange is provided between the pump body and the gear box. The shaft end of the screw passes through the intermediate flange and extends into the gear box. The sealing system is provided in the intermediate flange and includes a first oil seal and a second oil seal which are sequentially sleeved on the shaft end of the screw in the axial direction. The first oil seal is close to the high-pressure chamber side to seal the medium and form a sealing area in the high-pressure chamber. A lubricating ring is provided in the middle flange between the first oil seal and the second oil seal, and the lubricating ring is sleeved on the end of the screw shaft.

2. The vertical twin-screw pump secondary oil seal sealing system according to claim 1, characterized in that: A notch is provided on the gear box facing the middle flange side, and the notch and the upper end surface of the middle flange enclose a lubrication chamber. A constant position oil cup connected to the lubrication chamber is provided on the gear box located on one side of the lubrication chamber, and the constant position oil cup performs replenishment lubrication on the first oil seal and the second oil seal.

3. The vertical twin-screw pump secondary oil seal sealing system according to claim 2, characterized in that: A vent pipe communicating with the lubrication chamber is provided on the gear box located on one side of the lubrication chamber.

4. The vertical twin-screw pump secondary oil seal sealing system according to claim 2, characterized in that: A discharge valve communicating with the lubrication chamber is provided on the gear box located on one side of the lubrication chamber.

5. The vertical twin-screw pump secondary oil seal sealing system according to claim 1, characterized in that: A third oil seal is provided in the gear box at a position where the screw shaft end passes through, and the third oil seal sleeve is provided at the screw shaft end.

6. The vertical twin-screw pump secondary oil seal sealing system according to claim 1, characterized in that: Sealing rings are provided on the contact end surfaces between the pump body, the middle flange and the gear box.

7. The vertical twin-screw pump secondary oil seal sealing system according to claim 1, characterized in that: A mounting blind hole is provided in the middle flange at the position where the axial end of the screw passes through, and the first oil seal, the second oil seal and the lubricating ring are all provided in the mounting blind hole.

8. The vertical twin-screw pump secondary oil seal sealing system according to claim 1, characterized in that: The first oil seal and the second oil seal are high-pressure oil seals and can withstand a pressure of ≯2.5 MPa.

9. The vertical twin-screw pump secondary oil seal sealing system according to claim 1, characterized in that: The shaft section contacting the first oil seal and the second oil seal is hardened to form a hardened section.

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