Shaft end mechanical sealing device

Abstract

A shaft end mechanical sealing device relates to the technical field of pump shaft mechanical sealing devices, and comprises a shaft sleeve, a sealing seat, two moving rings, two static rings and a transmission ring, the two moving rings are respectively called an outer moving ring and an inner moving ring, the two static rings are respectively called an outer static ring and an inner static ring, the outer moving ring and the inner moving ring are respectively fixedly and hermetically matched with the shaft sleeve, and the outer moving ring and the inner moving ring are respectively fixedly and hermetically matched with the shaft sleeve. The outer static ring and the inner static ring are respectively matched with the sealing seat in a sliding and sealing mode, an outer spring is arranged between the outer static ring and the sealing seat, the outer static ring has the movement tendency of abutting against the outer moving ring under the elastic force effect of the outer spring, and an inner spring is arranged between the inner static ring and the sealing seat. And the inner static ring has the movement tendency of abutting against the inner moving ring under the elastic force action of the inner spring. The utility model solves the problem that the pump has to be forced to stop after the mechanical seal at the shaft end of the pump fails, and has two mechanical seals, and after the outer mechanical seal fails, the inner mechanical seal continues to play a role to ensure that the pump does not stop working.

Description

Technical Field

[0001] The utility model belongs to the technical field of pump shaft mechanical seal devices, and particularly relates to a shaft end mechanical seal device. Background Art

[0002] Mechanical seal refers to a device that prevents fluid leakage, which is composed of at least a pair of end faces perpendicular to the rotation axis. Under the action of fluid pressure and the elastic force (or magnetic force) of the compensation mechanism, and with the cooperation of auxiliary seals, the end faces remain in contact and relatively slide. The common mechanical seal structure consists of elements such as a stationary ring, a rotating ring, an elastic element, a rotating ring auxiliary seal ring, and a stationary ring auxiliary seal ring. The rotating ring is directly fixed on the pump shaft or fixed on the pump shaft through a shaft sleeve, and the stationary ring is directly fixed to the pump body.

[0003] The existing shaft end mechanical seal usually has a stationary ring and a rotating ring, forming a single mechanical seal. When the mechanical seal fails, there is no remedial measure, and the pump has to be forced to stop working, affecting the continuity of the project. Summary of the Utility Model

[0004] In order to solve the problems in the background art, the utility model provides a shaft end mechanical seal device. The utility model has two mechanical seals. When the outer mechanical seal is not damaged, the outer mechanical seal plays the main sealing role. When the outer mechanical seal is damaged, the inner mechanical seal can continue to play the mechanical seal role to ensure that the pump will not be forced to stop working.

[0005] The technical solution provided by the utility model is: a shaft end mechanical seal device, including a shaft sleeve, a seal seat, a rotating ring, a stationary ring, and a transmission ring. It is characterized in that: there are two rotating rings, which are respectively called an outer rotating ring and an inner rotating ring, and there are also two stationary rings, which are respectively called an outer stationary ring and an inner stationary ring. The outer rotating ring and the inner rotating ring are respectively fixedly and sealingly matched with the shaft sleeve, and the outer stationary ring and the inner stationary ring are respectively slidably and sealingly matched with the seal seat. An outer spring is arranged between the outer stationary ring and the seal seat. Under the elastic force of the outer spring, the outer stationary ring has a tendency to abut against the outer rotating ring. An inner spring is arranged between the inner stationary ring and the seal seat. Under the elastic force of the inner spring, the inner stationary ring has a tendency to abut against the inner rotating ring.

[0006] A further technical solution is: a circular groove is opened on the seal seat corresponding to the inner spring. A sliding ring is slidably and sealingly arranged in the circular groove. The inner spring abuts against the sliding ring. A hydraulic hole communicating with the circular groove is radially opened on the seal seat. A sliding plug is slidably and sealingly arranged in the hydraulic hole. A set screw is threadedly connected to the hydraulic hole outside the sliding plug. During the process of screwing in the set screw, the sliding plug is pushed to slide. The cavity between the sliding plug and the sliding ring is filled with lubricating oil. A retaining ring for preventing the inner stationary ring from approaching the inner rotating ring is arranged on the seal seat. A sleeve is arranged between the sliding ring and the inner stationary ring, and the two ends of the sleeve respectively abut against the sliding ring and the inner stationary ring.

[0007] A further technical solution is that the inner side of the sealing seat is provided with a step, and the step includes a reduced-diameter section and an enlarged-diameter section. The inner static ring and the retaining ring are both installed on the reduced-diameter section.

[0008] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0009] Compared with the prior art, the present utility model has two mechanical seals. Before the outer mechanical seal is damaged and fails, the outer mechanical seal plays a role; when the outer mechanical seal is damaged, the inner mechanical seal continues to play a role to ensure the continuous reliability of the mechanical seal. Description of the Drawings

[0010] Figure 1 is a sectional view of the present utility model.

[0011] In the figure: 1, pump shaft; 2, transmission ring; 3, sliding plug; 4, set screw; 5, hydraulic hole; 6, sliding ring; 7, sleeve; 8, inner static ring; 9, inner moving ring; 10, shaft sleeve; 11, outer moving ring; 12, outer static ring; 13, outer spring; 14, retaining ring; 15, inner spring; 16, annular groove; 17, sealing gasket; 18, sealing seat. Specific Embodiments

[0012] In order to enable those skilled in the art to better understand the solution of the present utility model, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0013] Refer to Figure 1 , a shaft-end mechanical seal device for a pump disclosed by the present utility model, the structure of which includes a shaft sleeve 10, a sealing seat 18, a moving ring, a static ring and a transmission ring 2. Among them, the moving ring is fixedly and sealingly connected to the shaft sleeve 10, the static ring is slidably and sealingly matched with the sealing seat 18, and the sealing seat 18 is connected to the pump body by bolts, and a sealing gasket 17 is provided at the connection. The above are the structures that already exist in the prior art and will not be elaborated here.

[0014] The innovation of this embodiment lies in that there are two moving rings, which are respectively called the outer moving ring 11 and the inner moving ring 9 for the convenience of distinction; there are also two static rings, which are respectively called the outer static ring 12 and the inner static ring 8 for the convenience of distinction. The outer moving ring 11 and the inner moving ring 9 are respectively fixedly and sealingly matched with the shaft sleeve 10, the shaft sleeve 10 is fixedly and sealingly matched with the pump shaft 1, the outer static ring 12 and the inner static ring 8 are respectively slidably and sealingly matched with the seal seat 18, an outer spring 13 is arranged between the outer static ring 12 and the seal seat 18, and under the elastic force of the outer spring 13, the outer static ring 12 has a tendency to abut against the outer moving ring 11. An inner spring 15 is arranged between the inner static ring 8 and the seal seat 18, and under the elastic force of the inner spring 15, the inner static ring 8 has a tendency to abut against the inner moving ring 9. As can be seen from the above, this embodiment has two mechanical seals. In the initial state, the two mechanical seals can be started simultaneously. However, at this time, the outer mechanical seal formed between the outer static ring 12 and the outer moving ring 11 plays a major role. Because no liquid flows through, the inner mechanical seal formed between the inner static ring 8 and the inner moving ring 9 basically does not play a role. But if the outer seal is damaged by pumped impurities and the outer mechanical seal fails, then the inner mechanical seal can immediately play a sealing role.

[0015] As a further technical solution, on the basis of the above, a circular groove 16 is opened on the seal seat 18 corresponding to the inner spring 15, and a sliding ring 6 is slidably and sealingly arranged in the circular groove 16, and the inner spring 15 abuts against the sliding ring 6. A hydraulic hole 5 communicating with the circular groove 16 is radially opened on the seal seat 18, a sliding plug 3 is slidably and sealingly arranged in the hydraulic hole 5, a setscrew 4 is threadedly connected in the hydraulic hole 5 outside the sliding plug 3, and when the setscrew 4 is screwed in, it pushes the sliding plug 3 to slide. The cavity between the sliding plug 3 and the sliding ring 6 is filled with lubricating oil, so when the sliding plug 3 slides downward, it will push the sliding ring 6 to slide. A retaining ring 14 for blocking the inner static ring 8 from approaching the inner moving ring 9 is arranged on the seal seat 18, and a sleeve 7 is arranged between the sliding ring 6 and the inner static ring 8, and both ends of the sleeve 7 abut against the sliding ring 6 and the inner static ring 8 respectively. The working process of this solution is as follows: In the initial state, under the blocking action of the retaining ring 14, the inner static ring 8 and the inner moving ring 9 are in a separated state. When the outer mechanical seal fails and air or liquid leaks from the pump shaft 1, the setscrew 4 is screwed in inward. The setscrew 4 pushes the sliding plug 3. Since the cavity between the sliding plug 3 and the sliding ring 6 is filled with lubricating oil, under the action of hydraulic thrust, the sliding ring 6 is pushed to slide. Further, the sliding ring 6 pushes the sleeve 7, the sleeve 7 pushes the inner static ring 8, and the inner static ring 8 pushes the retaining ring 14 away, and the fixed connection between the retaining ring 14 and the seal seat 18 is damaged. Therefore, the inner spring 15 can exert its elastic force, and under the elastic force of the inner spring 15, the inner static ring 8 abuts against the inner moving ring 9, forming an inner mechanical seal, and this embodiment can ensure the sustainability of the shaft-end mechanical seal of the pump.

[0016] To ensure that after the fixed connection between the retaining ring 14 and the sealing seat 18 is damaged, the retaining ring 14 does not obstruct the free sliding of the inner static ring 8, the inner side of the sealing seat 18 is provided with a step. The step includes a reduced-diameter section and an enlarged-diameter section. In the initial state, both the inner static ring 8 and the retaining ring 14 are installed on the reduced-diameter section. After the fixed connection is damaged, the retaining ring 14 enters the enlarged-diameter section, while the inner static ring 8 remains on the reduced-diameter section, thereby ensuring that the retaining ring 14 does not affect the free sliding of the inner static ring 8.

Claims

1. A shaft end mechanical seal device, comprising a shaft sleeve (10), a sealing seat (18), a dynamic ring, a static ring and a transmission ring (2), characterized in that: There are two moving rings, respectively referred to as an outer moving ring (11) and an inner moving ring (9); there are also two stationary rings, respectively referred to as an outer stationary ring (12) and an inner stationary ring (8); the outer moving ring (11) and the inner moving ring (9) are respectively fixedly sealed with the shaft sleeve (10); the outer stationary ring (12) and the inner stationary ring (8) are respectively slidably sealed with the sealing seat (18); an outer spring (13) is provided between the outer stationary ring (12) and the sealing seat (18); under the elastic force of the outer spring (13), the outer stationary ring (12) has a movement tendency to abut against the outer moving ring (11); an inner spring (15) is provided between the inner stationary ring (8) and the sealing seat (18); under the elastic force of the inner spring (15), the inner stationary ring (8) has a movement tendency to abut against the inner moving ring (9).

2. A shaft end mechanical seal device according to claim 1, characterized in that: An annular groove (16) is provided on the sealing seat (18) corresponding to the inner spring (15), and a sliding ring (6) is provided in the annular groove (16) as a sliding seal. The inner spring (15) abuts against the sliding ring (6). A hydraulic hole (5) communicating with the annular groove (16) is provided in the radial direction of the sealing seat (18), and a sliding plug (3) is provided in the hydraulic hole (5) as a sliding seal. A top screw (4) is connected to the inner thread of the hydraulic hole (5) outside the sliding plug (3). The top screw (4) pushes the sliding plug (3) to slide during the screwing process. The cavity between the sliding plug (3) and the sliding ring (6) is filled with lubricating oil. A retaining ring (14) is provided on the sealing seat (18) for preventing the inner static ring (8) from approaching the inner moving ring (9). A sleeve (7) is provided between the sliding ring (6) and the inner static ring (8), and the two ends of the sleeve (7) abut against the sliding ring (6) and the inner static ring (8) respectively.

3. A shaft end mechanical seal device according to claim 2, characterized in that: The inner side of the sealing seat (18) is provided with a step, the step comprising a reduced diameter section and an expanded diameter section, and the inner stationary ring (8) and the retaining ring (14) are both mounted on the reduced diameter section.

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