Emergency seal

Abstract

The invention relates to the field of mechanical seals, in particular to an emergency seal which comprises an emergency seal body arranged on an outer ring of a main shaft, the emergency seal body comprises an emergency moving ring coaxially fixed to the main shaft and an emergency static ring arranged on an end cover, and the end cover is provided with an emergency starter used for locking or unlocking the emergency static ring. When the emergency static ring is locked by the emergency starter, a distance exists between the end face of the emergency static ring and the emergency moving ring, a spring in a compressed state is arranged on the end cover in the direction parallel to the main shaft, and the spring applies elastic force towards the emergency moving ring to the emergency static ring. The emergency seal can be emergently started when the working seal fails, the power consumption of the shaft end sealing system is effectively reduced, the service life of the emergency seal is prolonged, and the reliability of the sealing system is improved.

Description

Technical Field

[0001] The invention relates to the field of mechanical seals, in particular to an emergency seal. Background Art

[0002] Mechanical seal refers to a device that prevents fluid leakage by at least one pair of end faces perpendicular to the axis of rotation, which are kept in close contact and slide relative to each other under the action of fluid pressure and the elastic force (or magnetic force) of the compensation mechanism and the cooperation of auxiliary seals. After long-term operation, the dynamic ring and the static ring of the mechanical seal are prone to wear due to long-term friction loss, resulting in seal failure and leakage.

[0003] In order to prevent leakage of the mechanical seal from affecting the operation of the host, the existing host, as described in the announcement number "CN215861730U", is equipped with a two-stage series mechanical seal to reduce pressure and control leakage in stages. However, although this series-designed combined mechanical seal can improve the sealing performance, it still has disadvantages. Since both stages of the mechanical seals are in working condition, their sealing end faces are in real-time wear, and the sealing power consumption will increase exponentially. Although the overall sealing performance of the device has been improved, the service life of the two-stage mechanical seals will be shortened as the host continues to work. When both sets of mechanical seals are worn out, leakage problems will still occur, so it is urgent to solve them. Summary of the invention

[0004] In order to avoid and overcome the technical problems existing in the prior art, the present invention provides an emergency seal. The emergency seal of the present invention can be activated in an emergency when the working seal fails, effectively reducing the power consumption of the shaft end sealing system, extending the service life of the emergency seal, and improving the reliability of the sealing system.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An emergency seal includes an emergency seal arranged on the outer ring of a main shaft, the emergency seal includes an emergency dynamic ring fixed coaxially with the main shaft and an emergency static ring arranged on an end cover, the end cover is provided with an emergency starter for locking or unlocking the emergency static ring, when the emergency static ring is locked by the emergency starter, there is a gap between the end face of the emergency static ring and the emergency dynamic ring, a spring in a compressed state is arranged on the end cover in a direction parallel to the main shaft, and the spring applies an elastic force on the emergency static ring in the direction of the emergency dynamic ring.

[0007] As a further solution of the present invention: the emergency starter includes a moving iron core arranged in the mounting hole of the end cover along the radial direction of the main shaft, and an electromagnetic coil coaxially arranged on the outer ring of the moving iron core for electromagnetic induction cooperation with the moving iron core; a positioning groove is provided on the emergency static ring seat where the emergency static ring is located, and a guide column penetrating the end cover is coaxially arranged on the moving iron core; the guide column is inserted into the positioning groove to lock the emergency static ring, and when the electromagnetic coil is energized, the moving iron core is driven to slide along the radial direction of the main shaft and disengage from the positioning groove to unlock the emergency static ring.

[0008] As a further solution of the present invention: a spring hole is opened in the end cover, and the spring is arranged in the spring hole, and applies an elastic force parallel to the axial direction of the main shaft to the emergency static ring seat; a return spring is coaxially arranged on the outer ring of the guide column, and the return spring applies an elastic force along the radial direction of the main shaft to the seat body of the guide column.

[0009] As a further solution of the present invention: a shaft sleeve is coaxially arranged on the outer ring of the main shaft, and a sealing ring is arranged on the mating surface of the shaft sleeve and the main shaft; the emergency moving ring seat and the emergency static ring seat are both arranged on the outer ring of the shaft sleeve; the emergency moving ring is fixed in the seat cavity of the emergency moving ring seat by a moving ring seat retaining ring, and the emergency static ring is fixed in the seat cavity of the emergency static ring seat by a static ring seat retaining ring.

[0010] As a further solution of the present invention: sealing rings are provided at the contact surfaces between the emergency moving ring seat, the shaft sleeve and the emergency moving ring; sealing rings are provided at the contact surfaces between the emergency static ring seat, the emergency static ring and the end cover; the emergency static ring seat and the emergency static ring are prevented from rotating by an anti-rotation pin.

[0011] As a further solution of the present invention: a pre-installed sheet is arranged on the end surface of the end cover, and a slot for the pre-installed sheet to be clamped and fixed is arranged on the shaft sleeve. The pre-installed sheet and the slot of the shaft sleeve are clamped and positioned to pre-install the end cover.

[0012] As a further solution of the present invention: the emergency seal is arranged in series with the working seal of the main shaft, and the maximum allowable leakage of the working seal is calculated. Calculation of the maximum permissible torque for the operating seal Measure the instantaneous leakage rate Q and instantaneous torque T of the working seal N ;

[0013] When satisfied And in the time interval (t, t+10s) When it is always less than 0, the emergency starter will lock the emergency static ring, otherwise the emergency starter will unlock the emergency static ring.

[0014] As a further solution of the present invention: the maximum allowable leakage of the working seal for:

[0015]

[0016] Among them, Di The inner diameter of the sealing end face of the working seal;

[0017] D o The outer diameter of the sealing end face of the working seal;

[0018] n is the spindle speed;

[0019] P i The inner diameter side pressure of the sealing end face of the working seal;

[0020] p o The pressure on the outer diameter side of the sealing end face of the working seal;

[0021] μ is the dynamic viscosity of the medium sealed by the working seal;

[0022] B is the balance ratio of the working seal.

[0023] As a further solution of the present invention: the maximum permissible torque of the working seal for:

[0024]

[0025] T 0max It is the maximum torque of the working seal measured during the start-up of the main engine.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The emergency seal of the present invention can be used as a backup seal. When the working seal fails, the emergency seal is unlocked by the emergency starter. Under the action of the spring, the emergency static ring seat is pushed to slide toward the emergency dynamic ring until the emergency static ring abuts against the emergency dynamic ring to form a sealing end face, so that the emergency seal can be used in an emergency when the working seal fails, effectively reducing the power consumption of the shaft end sealing system, extending the service life of the emergency seal, and improving the reliability of the sealing system.

[0028] 2. The present invention establishes a leakage calculation formula and a maximum allowable torque calculation formula to calculate the maximum allowable leakage and the maximum allowable torque of the working seal under the relevant working conditions, and measures and compares the instantaneous leakage rate and the instantaneous torque of the working seal to determine whether the standard for opening the emergency seal is met.

[0029] 3. The present invention drives the moving iron core to slide radially along the main shaft through the electromagnetic induction cooperation between the electromagnetic coil and the moving iron core, thereby realizing the locking and unlocking actions of the emergency static ring, which is convenient and quick. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the present invention.

[0031] Figure 2 This is a schematic diagram of the first working state of the emergency starter in the present invention.

[0032] Figure 3 It is a schematic diagram of the second working state of the emergency starter in the present invention.

[0033] In the figure:

[0034] 1. Main shaft; 2. Emergency seal;

[0035] 21. Emergency moving ring seat; 211. Emergency moving ring; 212. Moving ring seat retaining ring;

[0036] 22. Emergency stationary ring seat; 221. Emergency stationary ring; 222. Stationary ring seat retaining ring;

[0037] 223. Anti-rotation pin; 224. Positioning groove;

[0038] 23. End cover; 231. Spring; 24. Pre-installed sheet; 25. Emergency starter;

[0039] 251, moving iron core; 252, electromagnetic coil; 253, guide column; 254, return spring;

[0040] 3. Bushing. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] See also Figures 1 to 3 In an embodiment of the present invention, an emergency seal includes an emergency seal 2, which is coaxially arranged on the shaft sleeve 3 of the main shaft 1. The emergency seal 2 includes an emergency moving ring seat 21 and an emergency stationary ring seat 22. The emergency moving ring 211 is arranged in the seat cavity of the emergency moving ring seat 21, and the emergency moving ring 211 is axially limited by the moving ring seat retaining ring 212; the emergency stationary ring 221 is arranged in the seat cavity of the emergency stationary ring seat 22, and the emergency stationary ring 221 is axially limited by the stationary ring seat retaining ring 222. In this embodiment, the stationary ring assembly is a combination of parts including a stationary ring seat, an auxiliary seal and a retaining ring. In actual use, the stationary ring assembly can select an integrated single stationary ring, and the same applies to the moving ring assembly. The emergency stationary ring 221 and the emergency stationary ring seat 22 are fixed and positioned by an anti-rotation pin 223 to transmit torque.

[0043] An end cover 23 is coaxially arranged on the side of the main shaft 1 away from the medium cavity, and the emergency static ring seat 22 is installed on the end cover 23, and is positioned and stopped by an anti-rotation pin between the end cover 23. An emergency starter 25 is arranged on the end cover 23, which is used to lock or unlock the emergency static ring seat 22. When the emergency static ring seat 22 is in a locked state, the emergency static ring seat 22 cannot slide along the shaft sleeve 3. At this time, there is a gap between the emergency static ring 221 and the emergency dynamic ring 211, and a sealing mating surface cannot be formed. A through hole is opened on the end cover 23 for connecting the main machine.

[0044] The emergency starter 25 is preferably inserted and positioned with the emergency stationary ring seat 22 along the radial direction of the main shaft 1, and is arranged in the mounting hole of the end cover 23. The emergency starter 25 includes a moving iron core 251 and an electromagnetic coil 252 coaxially arranged on the outer ring of the moving iron core 251. A guide column 253 is coaxially arranged on the moving iron core 251, and a positioning groove 224 is provided on the emergency stationary ring seat 22 for inserting and positioning the guide column 253. When the emergency stationary ring seat 22 is locked, the guide column 253 passes through the end cover 23 and is inserted into the positioning groove 224 to limit the axial sliding of the emergency stationary ring seat 22 along the main shaft 1, thereby completing the locking of the emergency stationary ring seat 22. The size of the positioning groove 224 corresponds to the size of the guide column 253.

[0045] The electromagnetic coil 252 of the emergency starter 25 can be installed in the installation hole of the end cover 23 by means of threaded connection, elastic ring connection, interference connection, formed connection, bonding, etc.

[0046] The outer ring of the guide column 253 can be coaxially sleeved with a return spring 254. Under the elastic force of the return spring 254 in the radial direction of the main shaft 1, the guide column 253 is always inserted in the positioning groove 224. When the electromagnetic coil 252 is energized, under the action of electromagnetic induction, a force away from the axis of the main shaft 1 is applied to the moving iron core 251 in the radial direction of the main shaft 1, so that the guide column 253 is separated from the positioning groove 224, and the emergency stationary ring seat 22 is unlocked.

[0047] A spring 231 is installed in the emergency static ring seat 22. The spring 231 is axially arranged parallel to the main axis 1, and applies an elastic force to the emergency static ring seat 22 in the direction of the emergency dynamic ring 211. The spring 231 belongs to a static component, and the emergency static ring 221 is a compensation ring. The spring 231 can be replaced by other elastic elements such as a bellows. When the emergency static ring seat 22 is in a locked state, the spring 231 is in a compressed state. After the emergency starter 25 unlocks the emergency static ring seat 22, the spring 231 drives the emergency static ring seat 22 to slide in the direction of the emergency dynamic ring 211 until the emergency static ring 221 abuts against the emergency dynamic ring 211, thereby forming a sealing mating surface, and realizing the emergency start of the emergency seal 2. When the emergency seal 2 forms a sealing mating surface, its sealing form can be a balanced type or an unbalanced type.

[0048] The sleeve 3 is sleeved on the main shaft 1, and can transmit torque to the main shaft 1 through the pin. A sealing ring is arranged between the sleeve 3 and the main shaft 1 to prevent the medium from leaking to the atmosphere through the gap between the shafts. The sleeve 3 and the emergency dynamic ring seat 21 also transmit torque through the transmission pin, and the leakage channel between the emergency dynamic ring 211 and the sleeve 3 is blocked by the sealing ring.

[0049] A sealing ring is also provided between the emergency stationary ring seat 22 and the shaft sleeve 3 to block the leakage channel between the emergency stationary ring seat 22 and the shaft sleeve 3. The contact surface between the emergency stationary ring seat 22 and the emergency stationary ring 221 and the contact surface between the emergency dynamic ring seat 21 and the emergency dynamic ring 211 are both provided with sealing rings.

[0050] The end surface of the end cover 23 is provided with a pre-installed sheet 24, which is inserted into the slot of the shaft sleeve 3 and fixed to the end cover 23 by pre-installed screws. When the system is in normal working state, after determining the axial installation position of the shaft sleeve 3 and the end cover 23, the pre-installed sheet 24 is removed.

[0051] Set the emergency seal 2 in series with the working seal of the main shaft 1 and calculate the maximum allowable leakage of the working seal

[0052]

[0053] Among them, D i The inner diameter of the sealing end face of the working seal;

[0054] D o The outer diameter of the sealing end face of the working seal;

[0055] n is the speed of spindle 1;

[0056] P i The inner diameter side pressure of the sealing end face of the working seal;

[0057] p o The pressure on the outer diameter side of the sealing end face of the working seal;

[0058] μ is the dynamic viscosity of the medium sealed by the working seal;

[0059] B is the balance ratio of the working seal;

[0060] Calculation of the maximum permissible torque for the operating seal

[0061]

[0062] T 0max It is the maximum torque of the working seal measured during the start-up of the main engine;

[0063] Measure the instantaneous leakage rate Q and instantaneous torque T of the working seal N ;

[0064] When satisfied And in the time interval (t, t+10s) When the value is always less than 0, the emergency starter 25 locks the emergency static ring 221 , otherwise the emergency starter 25 unlocks the emergency static ring 221 .

[0065] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0066] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

Claims

1. An emergency seal, characterized in that: The invention comprises an emergency seal (2) arranged on the outer ring of a main shaft (1), the emergency seal (2) comprising an emergency moving ring (211) fixed coaxially with the main shaft (1) and an emergency static ring (221) arranged on an end cover (23), an emergency starter (25) for locking or unlocking the emergency static ring (221) is arranged on the end cover (23), when the emergency static ring (221) is locked by the emergency starter (25), there is a gap between the end face of the emergency static ring (221) and the emergency moving ring (211), and a spring (231) in a compressed state is arranged on the end cover (23) in a direction parallel to the main shaft (1), and the spring (231) applies an elastic force to the emergency static ring (221) in the direction of the emergency moving ring (211).

2. An emergency seal according to claim 1, characterized in that: The emergency starter (25) comprises a moving iron core (251) arranged in a mounting hole of an end cover (23) along the radial direction of the main shaft (1); an electromagnetic coil (252) coaxially arranged on the outer ring of the moving iron core (251) for electromagnetic induction cooperation with the moving iron core (251); a positioning groove (224) is provided on the emergency stationary ring seat (22) where the emergency stationary ring (221) is located; a guide column (253) penetrating the end cover (23) is coaxially arranged on the moving iron core (251); the guide column (253) is inserted into the positioning groove (224) to lock the emergency stationary ring (221); and when the electromagnetic coil (252) is energized, it drives the moving iron core (251) to slide radially along the main shaft (1) and disengage from the positioning groove (224) to unlock the emergency stationary ring (221).

3. An emergency seal according to claim 2, characterized in that: A spring hole is provided in the end cover (23), and a spring (231) is arranged in the spring hole and applies an elastic force parallel to the axial direction of the main shaft (1) to the emergency stationary ring seat (22); a return spring (254) is coaxially arranged on the outer ring of the guide column (253), and the return spring (254) applies an elastic force along the radial direction of the main shaft (1) to the seat body of the guide column (253).

4. An emergency seal according to any one of claims 1 to 3, characterized in that: A shaft sleeve (3) is coaxially arranged on the outer ring of the main shaft (1), and a sealing ring is arranged on the mating surface of the shaft sleeve (3) and the main shaft (1); an emergency moving ring seat (21) and an emergency stationary ring seat (22) are both arranged on the outer ring of the shaft sleeve (3); the emergency moving ring (211) is fixed in the seat cavity of the emergency moving ring seat (21) through a moving ring seat retaining ring (212), and the emergency stationary ring (221) is fixed in the seat cavity of the emergency stationary ring seat (22) through a stationary ring seat retaining ring (222).

5. An emergency seal according to any one of claims 1 to 3, characterized in that: Sealing rings are provided at the contact surfaces between the emergency moving ring seat (21), the shaft sleeve (3) and the emergency moving ring (211); sealing rings are provided at the contact surfaces between the emergency stationary ring seat (22), the emergency stationary ring (221) and the end cover (23); and the emergency stationary ring seat (22) and the emergency stationary ring (221) are anti-rotationally matched via an anti-rotation pin (223).

6. An emergency seal according to any one of claims 1 to 3, characterized in that: A pre-installed sheet (24) is arranged on the end surface of the end cover (23), and a slot for the pre-installed sheet (24) to be snap-fitted and fixed is arranged on the shaft sleeve (3). The pre-installed sheet (24) is snap-fitted and positioned with the slot of the shaft sleeve (3) to pre-install the end cover (23).

7. An emergency seal according to any one of claims 1 to 3, characterized in that: The emergency seal (2) is connected in series with the working seal of the main shaft (1) to calculate the maximum allowable leakage of the working seal. Calculation of the maximum permissible torque for the operating seal Measure the instantaneous leakage rate Q and instantaneous torque T of the working seal N ; When satisfied And in the time interval (t, t+10s) When the value is always less than 0, the emergency starter (25) locks the emergency static ring (221); otherwise, the emergency starter (25) unlocks the emergency static ring (221).

8. An emergency seal according to claim 7, characterized in that: Maximum allowable leakage of working seal for: Among them, D i The inner diameter of the sealing end face of the working seal; D o The outer diameter of the sealing end face of the working seal; n is the rotation speed of the spindle (1); P i The inner diameter side pressure of the sealing end face of the working seal; p o The pressure on the outer diameter side of the sealing end face of the working seal; μ is the dynamic viscosity of the medium sealed by the working seal; B is the balance ratio of the working seal.

9. An emergency seal according to claim 7, characterized in that: Maximum permissible torque for working seal for: T 0max It is the maximum torque of the working seal measured during the start-up of the main engine.

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