Mechanical sealing mechanism

Abstract

The utility model belongs to the technical field of sealing, and particularly relates to a mechanical sealing mechanism which comprises a first-stage seal, a second-stage seal and a transmission seat assembly. The first-stage seal comprises a first-stage static ring and a first-stage moving ring and is sleeved on the pump shaft; the second-stage seal comprises a second-stage static ring and a second-stage moving ring, and the end faces of the two rings are sealed; the transmission seat assembly is fastened on the shaft sleeve through an inner hexagon screw; the transmission seat assembly comprises a transmission seat, a first-stage push ring, a second-stage push ring, a continuous wave spring, a small spring, an anti-rotation pin and a hexagon socket set screw with a concave end; the first-stage seal and the second-stage seal are installed at the two ends of the transmission base assembly in the axial direction respectively. The back-to-back mechanical sealing device is generally suitable for back-to-back mechanical sealing of the Plan54 scheme, the sealing effect is good, and the service life is long. The movable ring is designed to be of a reverse balance structure, the hydraulic pressure difference is properly controlled and isolated while the reverse pressure is balanced, the structural seal also has wide applicability, the axial size of the movable ring is reduced to the maximum extent, and the movable ring is suitable for occasions with small axial space.

Description

Technical Field

[0001] The utility model belongs to the technical field of sealing, and particularly relates to a mechanical seal mechanism. Background Technique

[0002] For the Plan54 flushing scheme, the conventional seal design is to arrange two sets of balanced seals back to back. Under the working conditions that meet the seal design, the seal can work stably for a long time. However, in actual applications, the isolation liquid is often in a non-pressure or low-pressure state, resulting in premature failure of the primary seal. Improving the stability of the primary seal is the fundamental solution to the problem. In addition, in some cases, the space of the seal chamber is small, and the existing structure cannot meet the seal requirements. Content of the Utility Model

[0003] To solve the above technical problems, the utility model provides a mechanical seal mechanism, including a primary seal, a secondary seal and a drive seat assembly 7;

[0004] The primary seal includes a primary stationary ring 4 and a primary rotating ring 5, which are sleeved on the pump shaft and sealed at their end faces;

[0005] The secondary seal includes a secondary stationary ring 10 and a secondary rotating ring 9, which are sleeved on the pump shaft and sealed at their end faces;

[0006] The drive seat assembly 7 is fastened to the shaft sleeve by hexagon socket head cap screws and rotates with the pump shaft; the drive seat assembly 7 includes a drive seat 701, a primary push ring 702, a secondary push ring 703, a continuous wave spring 704, a small spring 705, an anti-rotation pin 706, and hexagon socket recessed set screws; the primary seal and the secondary seal are respectively installed at both axial ends of the drive seat assembly 7;

[0007] Among them, the continuous waveform spring 704 provides elastic compensation for the primary seal, and the small spring 705 provides elastic compensation for the secondary seal. The small spring 705 is designed according to the spring specific pressure and is arranged evenly along the circumferential direction. One end of the drive seat 701 has two inwardly protruding lugs 707, and the primary dynamic ring 5 is installed on the inner side. The lugs 707 are used to transmit torque to the primary dynamic ring 5. One end of the waveform spring 704 abuts against the drive seat 701, and the other end abuts against the primary push ring 702. The waveform spring 704 and the primary push ring 702 are limited in the drive seat 701 by the drive lug 707. The small springs 705 are evenly arranged in the counterbores on the axial end face of the drive seat 701. One end of the small spring 705 abuts against the counterbore, and the other end abuts against the secondary push ring 703. The spring is in a limited state. On this end face, there are also multiple counterbores for installing anti-rotation pins 706 along the circumferential direction. The anti-rotation pins 706 are installed in the counterbores, and the other end is connected to the secondary push ring 703. The secondary push ring 703 is provided with an inwardly protruding arc-shaped lug for transmitting torque to the secondary dynamic ring 9. The rotation torque of the secondary dynamic ring 9 is transmitted from the secondary push ring 703 to the anti-rotation pin 706, and then from the anti-rotation pin 706 to the drive seat 701.

[0008] Furthermore, the primary static ring 4 is provided with two shoulders. The shoulder at the friction pair end cooperates with the gland 12 to play an axial limiting role. On the other shoulder, a primary static ring seal ring 3 is provided. The primary static ring seal ring 3 plays a role in sealing the gland 12 and the primary static ring 4. There is an anti-rotation groove at the tail of the shoulder. The limit sleeve 2 is sleeved on the outside of the tail of the shoulder, and an anti-rotation pin 13 is provided to pass through the limit sleeve 2 and be fixed in the anti-rotation groove. One end face of the limit sleeve 2 abuts against the static ring seal ring 3, and the other end abuts against the snap ring 1. The inner hole of the limit sleeve 2 cooperates with the tail of the primary static ring 4, and the outside cooperates with the gland 12. The primary static ring 4 is positioned on the gland 12 through the limit sleeve 2 and the snap ring 1. The anti-rotation pin 13 of the limit sleeve 2 plays an anti-rotation role for the primary static ring 4.

[0009] Furthermore, the tail end of the secondary static ring 10 is provided with a shoulder, and a secondary static ring seal ring 11 is provided on this shoulder. The secondary static ring seal ring 11 is used to seal the gland and the secondary static ring 10.

[0010] Furthermore, multiple pin holes are provided at the tail end of the secondary static ring 10. The anti-rotation screw passes through the gland and is fastened to the shaft sleeve at the pin holes.

[0011] The utility model is generally applicable to the back-to-back mechanical seal of the Plan54 scheme, with good sealing effect and long service life. The dynamic ring is designed as a reverse balance structure, which can balance the reverse pressure and appropriately control the isolation hydraulic difference while having wide applicability. In addition, this seal minimizes the axial dimension and is suitable for occasions with small axial space. Description of the Drawings

[0012] Figure 1is a schematic structural diagram of the present utility model;

[0013] Figure 2 is a schematic structural diagram of the transmission assembly.

[0014] Among them, 1, snap ring; 2, limit sleeve; 3, static ring seal ring; 4, first-stage static ring; 5, first-stage dynamic ring; 6, first-stage dynamic ring seal ring; 7, transmission seat assembly; 701, transmission seat; 702, first-stage push ring; 703, second-stage push ring; 704, corrugated spring; 705, small spring; 706, anti-rotation pin; 707, transmission lug; 8, second-stage dynamic ring seal ring; 9, second-stage dynamic ring; 10, second-stage static ring; 11, second-stage static ring seal ring; 12, gland. Specific embodiments

[0015] The principle and characteristics of the present utility model will be described below with reference to the accompanying drawings. The examples given are only used to explain the present utility model and are not intended to limit the scope of the present utility model.

[0016] The key to the stable operation of the seal lies in whether there is a suitable working environment for the seal. While fully considering the structural and processing technology, in the case of a relatively small axial layout space for the seal, the first-stage seal static ring is limited, and the first-stage seal dynamic ring adopts a reverse balance structure to ensure the stable operation of the seal. The present utility model mainly aims to solve the problem of seal failure caused by the first-stage seal static ring being disengaged due to the isolation liquid pressure being lower than the medium pressure under special working conditions.

[0017] Refer to Figure 1 , the present utility model provides a mechanical seal mechanism, including a first-stage seal, a second-stage seal and a transmission seat 701 assembly 7; the first-stage seal and the second-stage seal share the transmission seat assembly.

[0018] The first-stage seal includes a first-stage static ring 4 and a first-stage dynamic ring 5, which are sleeved on the pump shaft, and the end faces of the two are sealed;

[0019] The second-stage seal includes a second-stage static ring 10 and a second-stage dynamic ring 9, which are sleeved on the pump shaft, and the end faces of the two are sealed;

[0020] Refer to Figure 2 , the transmission seat assembly 7 is fastened to the shaft sleeve by inner hexagon screws and rotates with the pump shaft; the transmission seat assembly 7 includes a transmission seat 701, a first-stage push ring 702, a second-stage push ring 703, a continuous corrugated spring 704, a small spring 705, an anti-rotation pin 706, and an inner hexagon socket set screw; the first-stage seal and the second-stage seal are respectively installed at both axial ends of the transmission seat assembly 7.

[0021] Among them, the continuous waveform spring 704 provides elastic compensation for the primary seal, and the small spring 705 provides elastic compensation for the secondary seal. The small spring 705 is designed according to the spring specific pressure and is evenly arranged along the circumferential direction. One end of the drive seat 701 has two inwardly protruding lugs 707, and the primary dynamic ring 5 is installed inside. The lugs 707 are used to transmit torque to the primary dynamic ring 5. One end of the waveform spring 704 abuts against the drive seat 701, and the other end abuts against the primary push ring 702. The waveform spring 704 and the primary push ring 702 are limited in the drive seat 701 by the drive lug 707. The small springs 705 are evenly arranged in the counterbores on the axial end face of the drive seat 701. One end of the small spring 705 abuts against the counterbore, and the other end abuts against the secondary push ring 703. The spring is in a limited state. There are also multiple counterbores for installing the anti-rotation pins 706 arranged along the circumferential direction on this end face. The anti-rotation pins 706 are installed in the counterbores, and the other end is connected to the secondary push ring 703. The secondary push ring 703 is provided with an inwardly protruding arc-shaped lug for transmitting torque to the secondary dynamic ring 9. The rotation torque of the secondary dynamic ring 9 is transmitted from the secondary push ring 703 to the anti-rotation pin 706, and then from the anti-rotation pin 706 to the drive seat 701.

[0022] The primary static ring 4 is provided with two shoulders. The shoulder at the friction pair end cooperates with the gland 12 to play an axial limiting role. An O-ring for the primary static ring 3 is arranged on the other shoulder. The O-ring for the primary static ring 3 functions to seal the gland 12 and the primary static ring 4. There is an anti-rotation groove at the tail of the shoulder. The limit sleeve 2 is sleeved outside the tail of the shoulder, and an anti-rotation pin 13 passes through the limit sleeve 2 and is fixed in the anti-rotation groove. One end face of the limit sleeve 2 abuts against the O-ring for the primary static ring 3, and the other end abuts against the snap ring 1. The inner hole of the limit sleeve 2 cooperates with the tail of the primary static ring 4, and the outside cooperates with the gland 12. The primary static ring 4 is positioned on the gland 12 through the limit sleeve 2 and the snap ring 1. The anti-rotation pin 13 of the limit sleeve 2 plays a role in preventing the rotation of the primary static ring 4.

[0023] As an improvement of the solution, a shoulder is provided at the tail end of the secondary static ring 10, and an O-ring for the secondary static ring 11 is arranged on this shoulder. The O-ring for the secondary static ring 11 is used to seal the gland and the secondary static ring 10.

[0024] Multiple pin holes are provided at the tail end of the secondary static ring 10. The anti-rotation screw passes through the gland and is fastened to the shaft sleeve at the pin holes.

[0025] The friction surface of the first-stage dynamic ring contacts with that of the first-stage static ring, and the dynamic and static rings move relative to each other during operation. A stepped groove is provided in the inner hole of the first-stage dynamic ring, and an O-ring, namely the first-stage dynamic ring seal 6, is provided in the groove for the floating seal between the dynamic ring and the shaft sleeve. The stepped inner hole of the dynamic ring designs the dynamic ring as a reverse balance structure. While balancing the reverse pressure, it appropriately controls the isolation hydraulic difference. This structure seal also has wide applicability. The most important thing is that this dynamic ring minimizes the axial dimension and is applicable to the occasions with small axial space. Rotating grooves are symmetrically arranged on the circumference of the dynamic ring and cooperate with the anti-rotation lug 707 of the transmission seat to transmit the rotational torque. The friction pair of the dynamic ring rotates in contact with the friction pair of the static ring, and the other end abuts against the first-stage push ring.

[0026] The second-stage dynamic ring adopts standard dimensions. One end abuts against the second-stage push ring, and the other end's friction pair rotates in contact with the friction pair of the static ring. The second-stage static ring is installed on the gland. During operation, the dynamic ring rotates with the pump shaft, and the static ring is fixed on the pump body by the gland. The friction pair realizes dynamic sealing, and the auxiliary O-ring, namely the second-stage static ring seal 11, realizes static sealing to ensure that the medium does not leak.

[0027] The installation sequence of the present utility model is as follows: clean the pump shaft, install the cartridge seal in the seal cavity, tighten the set screw, remove the positioning block, connect the flushing pipeline, adjust the isolation liquid pressure, and after checking by turning the shaft by hand, the equipment can be operated.

[0028] The first-stage sealing dynamic ring is designed as a reverse balance structure. While balancing the reverse pressure, it appropriately controls the isolation hydraulic difference. This structure seal also has wide applicability. The most important thing is that this dynamic ring minimizes the axial dimension and is applicable to the occasions with small axial space. For the first-stage seal, the inner pressure is called the reverse pressure. When the inner pressure is higher than the outer pressure, the balance coefficient of the dynamic ring is less than 1 when calculating the closing force of the friction pair, that is, the balance structure. The structure of the transmission seat in this scheme is ingeniously designed, reducing the seal dimension axially and being applicable to the chamber with small seal space.

[0029] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A mechanical seal mechanism, characterized in that, It includes a primary seal, a secondary seal and a drive seat (701) assembly (7); The primary seal includes a primary stationary ring (4) and a primary rotating ring (5), which are sleeved on the pump shaft and sealed at their end faces; The secondary seal includes a secondary stationary ring (10) and a secondary rotating ring (9), which are sleeved on the pump shaft and sealed at their end faces; The drive seat assembly (7) is fastened to the shaft sleeve by socket head cap screws and rotates with the pump shaft; the drive seat assembly (7) includes a drive seat (701), a primary push ring (702), a secondary push ring (703), a continuous wave spring (704), a small spring (705), an anti-rotation pin (706), and socket head cap screws with concave ends; the primary seal and the secondary seal are respectively installed at both axial ends of the drive seat assembly (7); Among them, the continuous wave spring (704) provides elastic compensation for the primary seal, and the small spring (705) provides elastic compensation for the secondary seal. The small spring (705) is designed according to the spring specific pressure and is evenly arranged circumferentially; there are two inwardly protruding lugs (707) at one end of the drive seat (701), and the primary rotating ring (5) is installed on the inner side. The lugs (707) are used to transmit torque to the primary rotating ring (5); one end of the wave spring (704) abuts against the drive seat (701), and the other end abuts against the primary push ring (702). The wave spring (704) and the primary push ring (702) are limited in the drive seat (701) by the drive lug (707); the small springs (705) are evenly arranged in the counterbored holes on the axial end face of the drive seat (701). One end of the small spring (705) abuts against the counterbored hole, and the other end abuts against the secondary push ring (703), and the spring is in a limited state; there are also multiple counterbored holes for installing the anti-rotation pins (706) arranged along the circumferential direction on this end face. The anti-rotation pins (706) are installed in the counterbored holes, and the other end is connected to the secondary push ring (703); the secondary push ring (703) is provided with an inwardly protruding arc-shaped lug for transmitting torque to the secondary rotating ring (9). The rotation torque of the secondary rotating ring (9) is transmitted from the secondary push ring (703) to the anti-rotation pin (706), and then from the anti-rotation pin (706) to the drive seat (701).

2. The mechanical seal mechanism according to claim 1, characterized in that, The primary stationary ring (4) is provided with two shoulders. The shoulder at the friction pair end cooperates with the gland (12) to play an axial limiting role; a primary stationary ring sealing ring (3) is arranged on the other shoulder. The primary stationary ring sealing ring (3) plays a role in sealing the gland (12) and the primary stationary ring (4). There is an anti-rotation groove at the tail of the shoulder; the limit sleeve (2) is sleeved on the outside of the tail of the shoulder, and an anti-rotation pin (13) passes through the limit sleeve (2) and is fixed in the anti-rotation groove; one end face of the limit sleeve (2) abuts against the stationary ring sealing ring (3), and the other end abuts against the snap ring (1). The inner hole of the limit sleeve (2) cooperates with the tail of the primary stationary ring (4), and the outside cooperates with the gland (12). The primary stationary ring (4) is positioned on the gland (12) through the limit sleeve (2) and the snap ring (1). The anti-rotation pin (13) of the limit sleeve (2) plays an anti-rotation role for the primary stationary ring (4).

3. A mechanical seal mechanism as claimed in claim 1, characterized in that, A shoulder is provided at the tail end of the secondary stationary ring (10), and a secondary stationary ring sealing ring (11) is provided on this shoulder. The secondary stationary ring sealing ring (11) is used to seal the gland and the secondary stationary ring (10).

4. A mechanical seal mechanism according to claim 3, characterized in that, A plurality of pin holes are provided at the tail end of the secondary stationary ring (10). The anti-rotation screw passes through the gland and is fastened to the shaft sleeve at the pin holes.

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