A seal assembly that automatically adjusts the seal gap and a multi-stage pump having the same

Abstract

The utility model discloses a kind of sealing assembly of automatic adjustment sealing gap and the multistage pump with the component, sealing assembly, including telescopic air bag, the air bag is provided with opening, the inner chamber of the air bag is provided with intermediate throttling bushing according to its telescopic process synchronous movement, the inside of the intermediate throttling bushing is fixedly provided with intermediate throttling shaft sleeve, the intermediate throttling bushing, intermediate throttling shaft sleeve between form the sealing gap that changes according to air bag telescoping, when applied to multistage pump, the intermediate throttling shaft sleeve is fixedly sleeved on pump shaft, the two ends of the intermediate throttling shaft sleeve respectively with positive flow assembly, reverse flow assembly abut;The utility model has the beneficial effect that: by telescopic air bag drive intermediate throttling bushing expansion or shrinkage, to meet the use requirement of different working conditions, further realize the adjustment of the size of sealing gap.

Description

Technical Field

[0001] This utility model relates to the field of water pump sealing technology, and in particular to a sealing component that automatically adjusts the sealing gap and a multi-stage pump having the component. Background Technology

[0002] Compared to traditional multistage pumps, self-balancing multistage pumps employ a back-to-back impeller arrangement, which can counteract the axial forces generated by the symmetrical impellers at each stage, achieving automatic axial force balance. This eliminates the need for the axial force balancing mechanism required in traditional multistage pumps, avoiding increased pump volume loss due to leakage in the axial force balancing mechanism. It also reduces malfunctions caused by the failure of the axial force balancing mechanism. Furthermore, the residual axial force of the self-balancing multistage pump is borne by the bearing at the pump end, improving the rigidity and critical speed of the pump rotor. This results in smooth and reliable operation, making it the mainstream drainage equipment in current mine drainage systems.

[0003] However, with the emergence of deep or ultra-deep mines in my country, high-lift, high-flow self-balancing multistage pumps have encountered some technical challenges, such as the wear resistance and cavitation resistance of flow components, the high pressure-bearing capacity of pressure-bearing components, and operating efficiency. Especially to meet the drainage needs of deep or ultra-deep mines, the number of stages in self-balancing multistage pumps has gradually increased, currently reaching 12 stages or more. According to the working principle of self-balancing multistage pumps, as the number of stages increases, the pressure difference across the outlet section also gradually increases. The intermediate throttling seal assembly is a key component for isolating high-pressure water from both sides of the outlet section, and its sealing performance directly affects the operating efficiency and stability of the self-balancing multistage pump. Currently, ordinary labyrinth seal structures are commonly used as intermediate throttling seal assemblies. However, with prolonged operation of the self-balancing multistage pump, the gap between the balancing bushing and the balancing shaft sleeve gradually increases, leading to a rapid increase in the volumetric loss of the self-balancing multistage pump, severely affecting the overall operating efficiency.

[0004] For example, the patent application number "CN202210662386.7" discloses "a structure of a self-balancing multi-stage pump shaft seal mechanical seal". However, this sealing structure cannot be adjusted according to the running time of the pump body. After the pump body has been running for a long time, the sealing gap may increase, affecting normal use. Utility Model Content

[0005] The purpose of this invention is to provide a sealing assembly that automatically adjusts the sealing gap and a multi-stage pump having the assembly, which can improve the pump's operating efficiency.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A sealing assembly for automatically adjusting a sealing gap includes a retractable airbag with an opening. An intermediate throttling bushing that moves synchronously with the airbag's expansion and contraction is provided in the inner cavity of the airbag. An intermediate throttling bushing is fixedly disposed inside the intermediate throttling bushing. A sealing gap that changes with the expansion and contraction of the airbag is formed between the intermediate throttling bushing and the intermediate throttling bushing.

[0008] Preferably, the airbag is covered with an airbag protective sleeve, and the airbag protective sleeve has a through hole that matches the airbag opening.

[0009] Preferably, a labyrinth sealing groove is provided on the side wall of the sealing gap formed by the intermediate throttling bushing and the intermediate throttling shaft sleeve.

[0010] Preferably, the intermediate throttling bushing includes a bushing upper structure and a bushing lower structure that cooperate with each other. One of the bushing upper structure and the bushing lower structure has a groove, and the other has a boss that cooperates with the groove. The depth of the groove is not less than the height of the boss.

[0011] Preferably, this utility model also provides a multi-stage pump with an automatically adjusting sealing gap sealing assembly. The pump includes a pump shaft, on which a coupling, a positive bearing assembly, an inlet section, a positive flow assembly, a reverse flow assembly, an outlet section, and a reverse bearing assembly are respectively arranged. The outlet section has a low-pressure chamber, a high-pressure chamber, and an inner chamber. The aforementioned automatically adjusting sealing gap sealing assembly is arranged on the outlet section. An intermediate throttling bushing is fixedly sleeved on the pump shaft, and the two ends of the intermediate throttling bushing abut against the positive flow assembly and the reverse flow assembly, respectively.

[0012] Preferably, the intermediate throttling bushing has a first step with an increased diameter at the end near the reverse flow assembly, and an upper adjustment gap is formed between the outer circumferential surface of the first step and the inner wall of the outlet section, and a lower adjustment gap is formed between the outer circumferential surface of the intermediate throttling bushing at the end near the forward flow assembly and the inner wall of the outlet section.

[0013] Preferably, the intermediate throttling bushing has a second step with a larger diameter at one end near the reverse flow assembly, and a wear-resistant layer is provided on the contact surface between the second step and the first step.

[0014] Preferably, the water outlet section has a high-pressure water hole that connects the high-pressure chamber and the inner cavity. One end of the high-pressure water hole that connects to the inner cavity is provided with a plug for sealing. The high-pressure water hole is connected to the airbag opening through a second water hole.

[0015] Preferably, the two ends of the airbag protective sleeve are respectively provided with a first sealing ring that contacts the first step and the inner wall of the water outlet section, and the outer circumferential wall of the airbag protective sleeve is provided with a second sealing ring that contacts the inner wall of the water outlet section.

[0016] The beneficial effects of this utility model are as follows:

[0017] 1. The expansion or contraction of the intermediate throttling bushing is driven by the retractable airbag, thereby adjusting the size of the sealing gap to meet the needs of different working conditions.

[0018] 2. The outer side of the airbag is fitted with an airbag protective sleeve, which can provide reliable protection for it. The middle throttling bushing is a split type, which can flexibly adjust the sealing gap as the airbag expands and contracts.

[0019] 3. During the operation of the pump, the pressure in the sealing gap will also change according to the changes in its working conditions. When the pressure is greater than the pressure in the air bladder, the split intermediate throttling bushing will squeeze the air bladder outward, thereby increasing the sealing gap and reducing the risk of system instability. When the pressure is less than the pressure in the air bladder, the air bladder will squeeze the split intermediate throttling bushing inward, thereby decreasing the sealing gap and effectively reducing leakage. Attached Figure Description

[0020] Figure 1 A full sectional view of a multistage pump with an automatically adjusting sealing gap assembly;

[0021] Figure 2 for Figure 1 The left view;

[0022] Figure 3 for Figure 1 Enlarged view of part number 6;

[0023] Figure 4 A schematic diagram of the upper structure of the bushing;

[0024] Figure 5 This is a structural diagram of the lower part of the bushing.

[0025] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Detailed Implementation

[0026] The present invention will now be further described with reference to the accompanying drawings.

[0027] Example 1

[0028] like Figure 3As shown, this embodiment discloses a sealing assembly for automatically adjusting the sealing gap, including a retractable airbag 63. The airbag 63 has an opening through which external media can be introduced into the airbag 63 or media can be discharged from the airbag 63. An intermediate throttling bushing 62 is provided inside the airbag 63. As the airbag 63 expands and contracts, the intermediate throttling bushing 62 will compress inward or expand outward (or, conversely, the airbag 63 will expand and contract accordingly as the intermediate throttling bushing 62 compresses inward or expands outward). An intermediate throttling bushing 61 is fixedly disposed inside the intermediate throttling bushing 62, and a sealing gap that changes according to the expansion and contraction of the airbag 63 is formed between the intermediate throttling bushing 62 and the intermediate throttling bushing 61.

[0029] An airbag protective sleeve 64 is provided on the outside of the airbag 63 to provide a certain degree of protection for the airbag 63. The airbag protective sleeve 64 has a through hole that matches the opening of the airbag 63, so that the medium can enter and exit from the airbag 63.

[0030] like Figure 4 and Figure 5 As shown, labyrinth sealing grooves 623 are provided on the side walls of the intermediate throttling bushing 62 and the intermediate throttling shaft sleeve 61 that form the sealing gap.

[0031] The intermediate throttling bushing 62 includes a bushing upper structure 621 and a bushing lower structure 622 that cooperate with each other. A groove 625 is provided on the contact surface between the bushing lower structure 622 and the bushing upper structure 621, while a boss 624 is provided on the contact surface between the bushing upper structure 621 and the bushing lower structure 622. The grooves 625 cooperate with each other so that the bushing upper structure 621 and the bushing lower structure 622 are combined to form the intermediate throttling bushing 62. The depth of the groove 625 is not less than the height of the boss 624, ensuring that there is no gap in the contact surface after the two are combined to form the intermediate throttling bushing 62.

[0032] Example 2

[0033] like Figure 1 and Figure 2 As shown, this utility model also provides a multi-stage pump with an automatically adjusting sealing gap sealing assembly, including a pump shaft 2. The pump shaft 2 is respectively provided with a coupling 1, a positive bearing assembly 3, an inlet section 4, a positive flow assembly 5, a reverse flow assembly 9, an outlet section 7, and a reverse bearing assembly 12. The outlet section 7 has a low-pressure chamber 71, a high-pressure chamber 72, and an inner chamber 73. The multi-stage pump also includes a transition pipe 8, a packing assembly 11, and a secondary inlet section 10. The specific structure of the aforementioned parts and the outlet section 7 are all conventional technologies of existing multi-stage pumps, and will not be described in detail in this embodiment.

[0034] The aforementioned automatic adjusting sealing gap sealing assembly is provided on the outlet section 7 of the multi-stage pump. The intermediate throttling bushing 61 is fixedly sleeved on the pump shaft 2, and the two ends of the intermediate throttling bushing 61 abut against the positive flow assembly 5 and the reverse flow assembly 9, respectively.

[0035] The intermediate throttling bushing 62 is provided with a first step with an increased diameter at one end near the reverse flow assembly 9. An upper adjustment gap 75 is formed between the outer circumferential surface of the first step and the inner wall of the outlet section 7. A lower adjustment gap 74 is formed between the outer circumferential surface of the intermediate throttling bushing 62 near the positive flow assembly 5 and the inner wall of the outlet section 7.

[0036] The intermediate throttling bushing 61 has a second step with a larger diameter at one end near the reverse flow assembly 9, and a wear-resistant layer 611 is provided on the contact surface between the second step and the first step. In this embodiment, the wear-resistant layer 611 is a hard alloy coating, which is deposited on the second step by plasma welding technology.

[0037] The water outlet section 7 is provided with a high-pressure water hole 65 that connects the high-pressure chamber 72 and the inner cavity 73. One end of the high-pressure water hole 65 that connects to the inner cavity 73 is provided with a plug 66 for sealing. The high-pressure water hole 65 is connected to the opening of the airbag 63 through the second water hole 67.

[0038] The airbag protective sleeve 64 has a first sealing ring at each end that contacts the first step and the inner wall of the water outlet section 7, respectively. A second sealing ring is provided on the outer circumferential wall of the airbag protective sleeve 64 that contacts the inner wall of the water outlet section 7. In this embodiment, both the first and second sealing rings are O-rings.

[0039] In this embodiment, the height of the boss 624 is 1.2mm, the depth of the slot 625 is 1.4mm, and the thickness of the wear-resistant layer 611 is set to 0.5mm.

[0040] In this embodiment, during assembly, the airbag protective sleeve 64 is installed in the inner hole of the outlet section 7 by an interference fit. During pump operation, when the fluid medium pressure in the low-pressure chamber 71 and high-pressure chamber 72 of the outlet section 7 is at the theoretical set value, the fluid medium in the high-pressure chamber 72 of the outlet section 7 passes through the through hole of the airbag protective sleeve 64 and enters the telescopic airbag 63 through the opening. At this time, the sealing gap between the intermediate throttling bushing 61 and the intermediate throttling bushing 62 is 0.5mm, the lower adjustment gap 74 of the bushing is 0.35mm, and the upper adjustment gap 75 of the bushing is 0.5mm. This state is the theoretical design state.

[0041] During normal pump operation, an axial force balancing structure similar to a balance disc is formed at the end faces of the intermediate throttling bushing 61 and the intermediate throttling bushing 62. When the fluid medium in the high-pressure chamber 72 of the outlet section 7 enters the transverse gap between the intermediate throttling bushing 61 and the intermediate throttling bushing 62 along the radial gap, it can effectively reduce the pressure of the fluid medium. At this time, the sealing fluid between the intermediate throttling bushing 61 and the intermediate throttling bushing 62 is prone to generate a strong sealing fluid excitation force under the rotation of the intermediate throttling bushing 61. When the sealing fluid excitation force generated by the sealing fluid is greater than the internal pressure of the telescopic air bladder 63, the intermediate throttling bushing 62, composed of the upper bushing structure 621 and the lower bushing structure 622, will gradually separate and squeeze the telescopic air bladder 63, thereby increasing the sealing gap between the intermediate throttling bushing 61 and the intermediate throttling bushing 62. The maximum sealing gap between the two is 1.0 mm (under theoretical design conditions, the intermediate throttling bushing 61 and the intermediate throttling bushing 62 are 1.0 mm). The sealing gap between the intermediate throttling bushing 62 is 0.5 mm, and the adjustment gap 75 on the bushing is 0.5 mm, which together equals the aforementioned 1.0 mm. This reduces the sealing excitation force of the sealing fluid and lowers the risk of instability in the rotor-seal mixing system. Conversely, when the self-balancing multistage pump is running, if the sealing fluid excitation force of the sealing gap between the intermediate throttling bushing 61 and the intermediate throttling bushing 62 is less than the internal pressure of the telescopic airbag, the telescopic airbag expands and squeezes the upper structure 621 and the lower structure 622 of the bushing, reducing the sealing gap between the intermediate throttling bushing 61 and the intermediate throttling bushing 62. The minimum sealing gap between them is 0.15 mm (in the theoretical design state, the sealing gap between the intermediate throttling bushing 61 and the intermediate throttling bushing 62 is 0.5 mm, and the adjustment gap 74 on the bushing is 0.35 mm, which together equals the aforementioned 0.15 mm), thereby effectively reducing the leakage of the intermediate throttling sealing assembly.

[0042] After long-term operation of the self-balancing multistage pump, the wear and erosion of the labyrinth seals of the intermediate throttling bushing 61 and intermediate throttling bushing 62 lead to an increase in the sealing gap between them. At this time, the sealing fluid excitation force between the intermediate throttling bushing 61 and intermediate throttling bushing 62 also gradually decreases. However, the fluid medium pressure entering the telescopic air bladder 63 from the high-pressure chamber of the outlet section 7 remains basically unchanged, causing the telescopic air bladder 63 to expand and squeeze the upper structure 621 and the lower structure 622 of the bushing, thereby adjusting the sealing gap between the intermediate throttling bushing 61 and intermediate throttling bushing 62. This avoids an increase in leakage due to the increased sealing gap between the two, and also effectively extends the service life of the intermediate throttling sealing assembly.

[0043] Furthermore, during the operation of the self-balancing multistage pump, an axial force balancing structure similar to a balance disc is formed at the end faces of the intermediate throttling bushing 61 and the intermediate throttling bushing 62. When the fluid medium in the high-pressure chamber of the outlet section 7 enters the transverse gap between the intermediate throttling bushing 61 and the intermediate throttling bushing 62 along the radial gap between them, the pressure of the fluid medium can be greatly reduced. At the same time, the fluid medium in the high-pressure chamber 72 of the outlet section 7 acts on the end face of the intermediate throttling bushing 61, which can offset part of the axial force generated during the operation of the self-balancing multistage pump, reducing the risk of bearing overheating caused by the bearing assembly bearing residual axial force for a long time.

[0044] The above embodiments are not intended to limit the shape, material, structure, etc. of this utility model in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this utility model shall fall within the protection scope of this utility model.

[0045] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this utility model and to simplify the description, 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 limiting the scope of protection of this utility model.

[0046] If the terms "first" or "second" are used in this document to define the components, those skilled in the art should know that the use of "first" or "second" is merely for the convenience of describing this utility model and simplifying the description, and unless otherwise stated, the above terms have no special meaning.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A sealing assembly for automatically adjusting the sealing gap, comprising a retractable airbag (63) having an opening thereon, characterized in that: The inner cavity of the airbag (63) is provided with an intermediate throttling bushing (62) that moves synchronously according to its expansion and contraction process. An intermediate throttling bushing (61) is fixedly provided inside the intermediate throttling bushing (62). A sealing gap that changes according to the expansion and contraction of the airbag (63) is formed between the intermediate throttling bushing (62) and the intermediate throttling bushing (61).

2. The sealing assembly for automatically adjusting the sealing gap according to claim 1, characterized in that, The airbag (63) is covered with an airbag protective sleeve (64), and the airbag protective sleeve (64) has a through hole that matches the opening of the airbag (63).

3. A sealing assembly for automatically adjusting the sealing gap according to claim 2, characterized in that, The intermediate throttling bushing (62) and intermediate throttling bushing (61) form a sealing gap with a labyrinth sealing groove (623) on their sidewalls.

4. A sealing assembly for automatically adjusting the sealing gap according to claim 3, characterized in that, The intermediate throttling bushing (62) includes a bushing upper structure (621) and a bushing lower structure (622) that cooperate with each other. One of the bushing upper structure (621) and the bushing lower structure (622) has a groove (625) and the other has a boss (624) that cooperates with the groove (625). The depth of the groove (625) is not less than the height of the boss (624).

5. A multi-stage pump with an automatically adjusting sealing gap sealing assembly, the pump comprising a pump shaft (2), on which a coupling (1), a positive bearing assembly (3), an inlet section (4), a positive flow assembly (5), a reverse flow assembly (9), an outlet section (7), and a reverse bearing assembly (12) are respectively arranged, wherein the outlet section (7) has a low-pressure chamber (71), a high-pressure chamber (72), and an inner chamber (73), characterized in that, The outlet section (7) is provided with a sealing assembly for automatically adjusting the sealing gap as described in any one of claims 2-4. The intermediate throttling bushing (61) is fixedly sleeved on the pump shaft (2). The two ends of the intermediate throttling bushing (61) abut against the positive flow assembly (5) and the reverse flow assembly (9), respectively.

6. A multi-stage pump with an automatically adjusting sealing gap sealing assembly according to claim 5, characterized in that, The intermediate throttling bushing (62) has a first step with a larger diameter at one end near the reverse flow assembly (9). An upper adjustment gap (75) is formed between the outer circumferential surface of the first step and the inner wall of the outlet section (7). A lower adjustment gap (74) is formed between the outer circumferential surface of the intermediate throttling bushing (62) near the positive flow assembly (5) and the inner wall of the outlet section (7).

7. A multi-stage pump with an automatically adjusting sealing gap sealing assembly according to claim 6, characterized in that, The intermediate throttling bushing (61) has a second step with a larger diameter at one end near the reverse flow assembly (9), and a wear-resistant layer (611) is provided on the contact surface between the second step and the first step.

8. A multi-stage pump with an automatically adjusting sealing gap sealing assembly according to claim 5, characterized in that, The water outlet section (7) is provided with a high-pressure water hole (65) that connects the high-pressure chamber (72) and the inner cavity (73). A plug wire (66) for sealing is provided at one end of the high-pressure water hole (65) that connects to the inner cavity (73). The high-pressure water hole (65) is connected to the opening of the airbag (63) through the second water hole (67).

9. A multi-stage pump with an automatically adjusting sealing gap sealing assembly according to claim 6, characterized in that, The airbag protective sleeve (64) is provided with a first sealing ring at both ends that contacts the first step and the inner wall of the water outlet section (7), and a second sealing ring is provided on the outer circumferential wall of the airbag protective sleeve (64) that contacts the inner wall of the water outlet section (7).

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