Mechanical seal device controllable online

Abstract

The application discloses an online-adjustable mechanical sealing device, which comprises a rotating ring, a stationary ring, a contact signal sensor and an adjuster. The stationary ring is arranged in an axial end-to-end mode with the rotating ring. The stationary ring is supported on a stationary ring seat via a pushing ring, a spring and a secondary seal. The secondary seal is arranged between the outer peripheral wall of the pushing ring and the inner peripheral wall of the stationary ring seat. The contact signal sensor is used for monitoring the end face contact degree between the rotating ring and the stationary ring. The adjuster is arranged in the stationary ring seat and closely arranged around the secondary seal. The adjuster is used for controlling the compression amount of the secondary seal according to the end face contact degree monitored by the contact signal sensor, so as to adjust the following performance of the sealing system online. The application can realize online adjustment and control of the secondary seal performance, reduce the end face wear of the mechanical seal, prevent safety accidents and avoid economic losses.

Description

Technical Field

[0001] The present invention relates to the technical field of active control of mechanical seals, and in particular to a mechanical seal device capable of online regulation. Background Art

[0002] Mechanical seals are generally used as shaft end seals for rotating mechanical equipment. They can operate under higher parameters and are widely used in petrochemical, nuclear energy, aerospace and other fields.

[0003] like Figure 9 As shown in Figure 1, a typical mechanical seal structure includes a dynamic ring, a static ring, a spring, and a secondary seal, with the spring and secondary seal forming the flexible support structure of the mechanical seal. Under normal operation, due to the excellent followability of the sealing system, mechanical seal end face contact is controlled within a reasonable range (no contact occurs between the dry gas seal end faces). However, abnormal operating conditions or unstable disturbances can cause excessive contact forces between the mechanical seal end faces. In particular, assembly errors and failure of the flexible support can degrade the followability of the sealing system, leading to abnormal contact between the mechanical seal end faces. Deterioration of the secondary seal is considered the primary cause of failure.

[0004] In summary, it is necessary to actively control the flexible support of mechanical seals, which can alleviate the abnormal state of the sealing system. Some research has been done on the active control of the flexible support of mechanical seals. The performance of the flexible support of the compensation ring can be changed by adjusting the spring pressure ratio online. However, the secondary seal is the main factor affecting the performance of the flexible support of the seal. At present, it is not possible to adjust the secondary seal online during the operation of the mechanical seal. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide an online adjustable mechanical seal device that can achieve online adjustment of the secondary seal performance, reduce mechanical seal end face wear, and avoid economic losses.

[0006] An online adjustable mechanical sealing device according to an embodiment of the present invention includes:

[0007] dynamic ring;

[0008] A stationary ring, the stationary ring and the dynamic ring are arranged end to end in the axial direction, the stationary ring is floatingly supported on the stationary ring seat via a push ring, a spring and a secondary seal, and the secondary seal is arranged between the outer peripheral wall of the push ring and the inner peripheral wall of the stationary ring seat;

[0009] A contact signal sensor, the contact signal sensor is used to monitor the degree of end face contact between the dynamic ring and the static ring;

[0010] An adjuster is located in the stationary ring seat and is closely arranged around the secondary seal, and is used to control the compression amount of the secondary seal according to the end face contact degree monitored by the contact signal sensor, so as to adjust the tracking performance of the sealing system online.

[0011] The online adjustable mechanical sealing device of the embodiment of the present invention is based on the traditional mechanical sealing device. By tightly arranging a regulator around the secondary seal, the regulator controls the compression of the secondary seal in real time online according to the change in the end face contact strength monitored by the contact signal sensor, changes the stiffness and damping of the secondary seal, adjusts and improves the tracking performance of the sealing system, reduces the contact force of the mechanical seal end face, and reduces the wear of the mechanical seal end face, which has great positive significance for the healthy operation of the equipment. At the same time, by adjusting the compression of the secondary seal online through the regulator, the economic losses caused by multiple shutdowns and disassembly of the secondary seal in the mechanical sealing device in the prior art can be avoided.

[0012] In some embodiments, the regulator is a piezoelectric ceramic.

[0013] In some embodiments, the piezoelectric ceramic is tightly disposed on the radial outer periphery of the secondary seal.

[0014] In some embodiments, a first annular recessed hole is provided on the stationary ring seat, and the first annular recessed hole is open relative to the axial distal end of the dynamic ring. The piezoelectric ceramic and the secondary seal are arranged in the first annular recessed hole, and the proximal side of the piezoelectric ceramic relative to the dynamic ring and the proximal side of the secondary seal relative to the dynamic ring are both abutted against the axial distal end surface of the first annular recessed hole, and the secondary seal is limited relative to the distal side of the dynamic ring by a limit sleeve arranged in the first annular recessed hole.

[0015] In some embodiments, the axial distal end surface of the first annular recess includes a step surface formed by a first annular radial surface, a first inner circumferential surface, a second annular radial surface, and a second inner circumferential surface connected in sequence from inside to outside and from near to far, wherein the secondary seal abuts against the first annular radial surface relative to the proximal side of the dynamic ring, and the piezoelectric ceramic abuts against the second annular radial surface and the second inner circumferential surface respectively relative to the proximal side and the outer side of the dynamic ring.

[0016] In some embodiments, the piezoelectric ceramic is a ring-shaped piezoelectric ceramic; or the piezoelectric ceramic is a circular arc segment piezoelectric ceramic, and there are multiple circular arc segment piezoelectric ceramics, and the multiple circular arc segment piezoelectric ceramics are connected by an arc-shaped support to form a ring structure.

[0017] In some embodiments, the piezoelectric ceramic is tightly disposed on an axial end of the secondary seal.

[0018] In some embodiments, a second annular recessed hole is provided on the stationary ring seat, and the second annular recessed hole is open relative to the axial distal end of the dynamic ring. The piezoelectric ceramic and the secondary seal are arranged in the second annular recessed hole. The piezoelectric ceramic is located on the distal side of the secondary seal relative to the dynamic ring so that the secondary seal abuts against the axial distal end surface of the second annular recessed hole relative to the proximal side of the dynamic ring. The piezoelectric ceramic is limited relative to the distal side of the dynamic ring by a limiting member provided in the second annular recessed hole.

[0019] In some embodiments, a retaining ring with a wedge-shaped radial cross section is further included. The retaining ring has a wedge-shaped surface. The retaining ring is arranged between the piezoelectric ceramic, the inner circumferential wall of the second annular recess and the secondary seal, and the wedge-shaped surface abuts against the secondary seal.

[0020] In some embodiments, the limiting member is fixed on the inner peripheral wall of the second annular recess.

[0021] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0023] Figure 1 A schematic cross-sectional view of an online adjustable mechanical sealing device according to an embodiment of the present invention;

[0024] Figure 2 for Figure 1 A magnified schematic diagram of point A in the middle;

[0025] Figure 3 A schematic diagram of a piezoelectric ceramic according to the present invention;

[0026] Figure 4 A schematic cross-sectional view of an online adjustable mechanical sealing device according to another embodiment of the present invention;

[0027] Figure 5 for Figure 4 The enlarged schematic diagram of point B in the middle;

[0028] Figure 6 A schematic cross-sectional view of an online adjustable mechanical sealing device according to another embodiment of the present invention;

[0029] Figure 7 for Figure 6 The enlarged schematic diagram of point C in the middle;

[0030] Figures 8a to 8cThis is a schematic diagram of the results of setting different flexible support stiffnesses and damping coefficients in a full numerical simulation model to verify the tracking performance of the piezoelectric ceramic 4a in regulating the sealing system;

[0031] Figure 9 It is a cross-sectional schematic diagram of an existing mechanical sealing device.

[0032] Reference numerals:

[0033] A mechanical sealing device 1000 capable of online adjustment and control; a dynamic ring 1; a stationary ring 2; a contact signal sensor 3; a regulator 4; a piezoelectric ceramic 4a; a sleeve 5; a sleeve 6; a push ring 7; a spring 8; a secondary seal 9; a stationary ring seat 10; a first annular recess 101; a first annular radial surface 1011; a first inner circumferential surface 1012; a second annular radial surface 1013; a second inner circumferential surface 1014; a limiting sleeve 11; a second annular recess 102; an arc-shaped support 12; a limiting member 13; a retaining ring 14; and a wedge-shaped surface 141. DETAILED DESCRIPTION

[0034] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0035] The following combination Figures 1 to 8c The online adjustable mechanical sealing device 1000 according to an embodiment of the present invention will be described.

[0036] like Figure 1 、 Figure 4 and Figure 6 As shown, the online adjustable mechanical seal device 1000 according to an embodiment of the present invention is a fluid sealing device, such as a dry gas sealing device. The online adjustable mechanical seal device 1000 according to the embodiment of the present invention includes a dynamic ring 1, a static ring 2, a contact signal sensor 3 and a regulator 4.

[0037] Specifically, the dynamic ring 1 is made of a hard material and is fixedly connected to a shaft (not shown) via a shaft sleeve 5 and a sleeve 6, so that the dynamic ring 1, the shaft sleeve 5 and the sleeve 6 rotate together with the shaft.

[0038] The stationary ring 2 is made of soft material and is axially aligned with the dynamic ring 1 (i.e. Figure 1 、 Figure 4 and Figure 6The two rings are arranged end-to-end (in the left-right direction as shown in the figure). The stationary ring 2 is floatingly supported on the stationary ring seat 10 via a push ring 7, a spring 8, and a secondary seal 9. The secondary seal 9 is positioned between the outer circumference of the push ring 7 and the inner circumference of the stationary ring seat 10. The spring 8 and secondary seal 9 form a flexible support. The dynamic ring 1 rotates while the static ring 2 does not rotate. The friction pair between the dynamic and static rings 1 and 2 acts as a mechanical seal (also known as a rotary seal). During mechanical seal operation, the static ring 2 is buoyant and designed to maintain a relatively stable relative motion relationship between its end face and the end face of the dynamic ring 1 under the action of various forces. Specifically, the fluid film between the dynamic and static rings 1 and 2 has a certain stiffness. As the relative positions of the dynamic and static rings 1 and 2 change, the force exerted by the friction pair on the static ring 2 will vary to resist such changes, maintaining a relatively stable relative motion relationship between the end faces of the static ring 2 and the dynamic ring 1. This prevents excessive leakage due to excessive distance between the static ring 2 and the dynamic ring 1, or rapid damage due to contact.

[0039] The contact signal sensor 3 can be an acoustic emission sensor and installed on the static ring 2. The contact signal sensor 3 is used to monitor the degree of end face contact between the dynamic ring 1 and the static ring 2. It is understandable that although the mechanical seal end face is designed not to have solid contact friction during normal and stable operation, substandard manufacturing of the secondary seal 9, assembly errors, abnormal jamming during operation and other faults will cause the following performance of the sealing system to deteriorate, that is, the following ability of the static ring 2 to the dynamic ring 1 will deteriorate, resulting in solid contact friction of the mechanical seal end face. The solid contact friction of the mechanical seal end face will generate a signal monitored by the contact signal sensor 3 on the one hand, that is, the contact signal sensor 3 monitors the end face contact degree or the change in the end face contact strength between the dynamic ring 1 and the static ring 2. On the other hand, it will cause wear to the static ring 2 and gradually damage the static ring 2.

[0040] The regulator 4 is located in the stationary ring seat 10 and is tightly arranged around the secondary seal 9. It is used to control the compression of the secondary seal 9 according to the end face contact degree monitored by the contact signal sensor 3, so that the stiffness and damping of the secondary seal 9 change, so as to online adjust the tracking performance of the sealing system, that is, to improve the tracking ability of the stationary ring 2 to the dynamic ring 1, so that the end face of the stationary ring 2 and the end face of the dynamic ring 1 maintain a relatively stable relative motion relationship, thereby reducing the contact force of the mechanical seal end face and reducing the wear of the mechanical seal end face, which has great positive significance for the healthy operation of the equipment. At the same time, by adjusting the compression of the secondary seal 9 online through the regulator 4, the economic losses caused by multiple shutdowns and disassembly of the secondary seal in the mechanical sealing device in the prior art can be avoided.

[0041] The online adjustable mechanical sealing device 1000 of the embodiment of the present invention is based on the traditional mechanical sealing device. By tightly arranging the regulator 4 around the secondary seal 9, the regulator 4 controls the compression amount of the secondary seal 9 in real time online according to the changes in the end face contact strength monitored by the contact signal sensor 3, changes the stiffness and damping of the secondary seal 9, adjusts and improves the tracking performance of the sealing system, reduces the contact force of the mechanical seal end face, and reduces the wear of the mechanical seal end face, which has great positive significance for the healthy operation of the equipment. At the same time, by adjusting the compression amount of the secondary seal 9 online through the regulator 4, the economic losses caused by multiple shutdowns and disassembly of the secondary seal in the mechanical sealing device in the prior art can be avoided.

[0042] In some embodiments, the regulator 4 is a piezoelectric ceramic 4a. By controlling the voltage of the piezoelectric ceramic 4a, the piezoelectric ceramic 4a is deformed, thereby causing the compression of the secondary seal 9 to change. The piezoelectric ceramic 4a is tightly installed around the secondary seal 9, and the piezoelectric ceramic 4a is powered in advance to pre-tighten the secondary seal 9. During the operation of the mechanical seal, the control method of the piezoelectric ceramic 4a is as follows: if the dynamic ring 1 and the static ring 2 have mechanical seal end face contact due to poor tracking performance of the sealing system, it will be detected by the contact signal sensor 3. At this time, the compression of the secondary seal 9 can be reduced by reducing the voltage of the piezoelectric ceramic 4a, thereby reducing the stiffness and damping of the secondary seal 9 and improving the tracking performance of the sealing system; if the tracking performance of the sealing system needs to be significantly adjusted, a negative voltage can be applied to the piezoelectric ceramic 4a until the contact sensor signal weakens. In this way, the compression of the secondary seal 9 can be adjusted online through the piezoelectric ceramic 4a to improve the tracking performance of the sealing system.

[0043] Different flexible support stiffness and damping coefficients are set in the full numerical simulation model to verify the following performance of the piezoelectric ceramic 4a regulating sealing system (such as Figures 8a to 8c As shown in Figure 8(a), the flexible support stiffness and damping are mainly generated by the secondary seal 9. The axial stiffness of the flexible support in Figure 8(a) is 8.2×10 5 N / m, angular stiffness is 1550kg·m 2 / s 2 , axial damping is 50000kg / s, angular damping is 70kg·m 2 / s, the flexible support parameter of Figure 8(b) is twice that of Figure 8(a), and the flexible support parameter of Figure 8(c) is three times that of Figure 8(a). The rotation speed of the dynamic ring 1 is 600 rpm, and the tilt angle of the dynamic ring 1 is 3.5×10 -4It can be found that when the flexible support parameter is larger, the contact force peak between the dynamic ring 1 and the static ring 2 increases. The contact force peak increases from about 5.5N (see Figure 8(a)) to 24N (see Figure 8(b)) and even 45N (see Figure 8(c)). It can be found that adjusting the stiffness and damping of the secondary seal 9 can significantly reduce the contact degree between the dynamic ring 1 and the static ring 2, reduce end face wear, and have great significance for the healthy operation of the seal and even the entire equipment.

[0044] In some embodiments, as Figure 1 and Figure 2 As shown, the piezoelectric ceramic 4a is tightly arranged on the radial outer periphery of the secondary seal 9. Thus, the stiffness and damping of the secondary seal 9 are changed by online controlling the radial compression of the secondary seal 9 by the piezoelectric ceramic 4a, thereby adjusting and improving the tracking performance of the sealing system.

[0045] In some embodiments, as Figure 1 and Figure 2 As shown, the stationary ring seat 10 is provided with a first annular recess 101 open at the axial distal end relative to the dynamic ring 1, the piezoelectric ceramic 4a and the secondary seal 9 are arranged in the first annular recess 101, the piezoelectric ceramic 4a is tightly arranged on the radial outer periphery of the secondary seal 9, the proximal side of the piezoelectric ceramic 4a relative to the dynamic ring 1 and the proximal side of the secondary seal 9 relative to the dynamic ring 1 both abut against the axial distal end surface of the first annular recess 101, and the distal side of the secondary seal 9 relative to the dynamic ring 1 is limited by a limiting sleeve 11 provided in the first annular recess 101. Therefore, by providing the first annular recess 101, the installation of the piezoelectric ceramic 4a and the secondary seal 9 is facilitated, and the lead-out of the wires of the piezoelectric ceramic 4a is also facilitated.

[0046] In some embodiments, as Figure 1 and Figure 2 As shown, the axial distal end surface of the first annular recess 101 includes a first annular radial surface 1011, a first inner circumferential surface 1012, a second annular radial surface 1013 and a second inner circumferential surface 1014 from inside to outside and from near to far (from near to far here is Figure 1 and Figure 2 The secondary seal 9, which can be understood as a stepped surface formed sequentially from left to right, abuts the first annular radial surface 1011 on the proximal side relative to the dynamic ring, while the piezoelectric ceramic 4a abuts the second annular radial surface 1013 and the second inner circumferential surface 1014 on the proximal side and outer side relative to the dynamic ring 1, respectively. This ensures convenient and reliable installation of the piezoelectric ceramic 4a and the secondary seal 9.

[0047] In some embodiments, the piezoelectric ceramic 4a is a circular piezoelectric ceramic; or Figure 3As shown, the piezoelectric ceramic 4a is an arc segment shaped piezoelectric ceramic, which is easier to manufacture than an integrated circular ring shaped piezoelectric ceramic. There are multiple arc segment shaped piezoelectric ceramics, and multiple arc segment shaped piezoelectric ceramics are connected by an arc shaped support 12 to form a circular ring structure to increase the stability of the assembly structure.

[0048] In some implementations, such as Figures 4 to 7 As shown, the piezoelectric ceramic 4a is tightly arranged on the axial end of the secondary seal 9. Thus, the stiffness and damping of the secondary seal 9 are changed by online controlling the axial compression of the secondary seal 9 through the piezoelectric ceramic 4a, thereby adjusting and improving the tracking performance of the sealing system.

[0049] In some embodiments, as Figures 4 to 7 As shown, a second annular recess 102 is provided on the stationary ring seat 10. The axial distal end of the second annular recess 102 relative to the dynamic ring 1 is open. The piezoelectric ceramic 4a and the secondary seal 9 are arranged in the second annular recess 102. The piezoelectric ceramic 4a is located on the distal side of the secondary seal 9 relative to the dynamic ring 1, so that the proximal side of the secondary seal 9 relative to the dynamic ring 1 abuts against the axial distal end surface of the second annular recess 102. The distal side of the piezoelectric ceramic 4a relative to the dynamic ring 1 is limited by a limiter 13 provided in the second annular recess 102. Therefore, by providing the second annular recess 102, the installation of the piezoelectric ceramic 4a and the secondary seal 9 is facilitated, and the lead-out of the wires of the piezoelectric ceramic 4a is also facilitated.

[0050] In some embodiments, as Figure 6 and Figure 7 As shown, the retaining ring 14 is further provided with a wedge-shaped radial cross section. The retaining ring 14 has a wedge-shaped surface 141. The retaining ring 14 is disposed between the piezoelectric ceramic 4a, the inner peripheral wall of the second annular recess 102, and the secondary seal 9. The wedge-shaped surface 141 abuts against the secondary seal 9. This improves the uniformity of the compression control of the secondary seal 9.

[0051] In some embodiments, as Figure 6 and Figure 7 The limiting member 13 is fixed on the inner peripheral wall of the second annular recessed hole 102 , and has a simple structure and reasonable arrangement.

[0052] It should be noted that the use of directional words such as "left" and "right" in the present invention is only for the convenience of description and does not specifically limit the scope of protection of the present invention.

[0053] Throughout this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" indicate that the specific features, structures, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0054] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A mechanical sealing device that can be adjusted online, characterized in that: include: dynamic ring; A stationary ring, the stationary ring and the dynamic ring are arranged end to end in the axial direction, the stationary ring is floatingly supported on the stationary ring seat via a push ring, a spring and a secondary seal, and the secondary seal is arranged between the outer peripheral wall of the push ring and the inner peripheral wall of the stationary ring seat; A contact signal sensor, the contact signal sensor is used to monitor the degree of end face contact between the dynamic ring and the static ring; An adjuster is located in the stationary ring seat and is closely arranged around the secondary seal, and is used to control the compression amount of the secondary seal according to the end face contact degree monitored by the contact signal sensor, so as to adjust the tracking performance of the sealing system online.

2. The online adjustable mechanical sealing device according to claim 1, characterized in that: The regulator is piezoelectric ceramic.

3. The online adjustable mechanical sealing device according to claim 2, characterized in that: The piezoelectric ceramic is tightly arranged on the radial outer periphery of the secondary seal.

4. The online adjustable mechanical sealing device according to claim 3, characterized in that: A first annular recessed hole is provided on the stationary ring seat, and the first annular recessed hole is open relative to the axial distal end of the dynamic ring. The piezoelectric ceramic and the secondary seal are arranged in the first annular recessed hole. The proximal side of the piezoelectric ceramic relative to the dynamic ring and the proximal side of the secondary seal relative to the dynamic ring are both in contact with the axial distal end surface of the first annular recessed hole, and the secondary seal is limited relative to the distal side of the dynamic ring by a limit sleeve arranged in the first annular recessed hole.

5. The online adjustable mechanical sealing device according to claim 4, characterized in that: The axial distal end surface of the first annular recess includes a step surface formed by a first annular radial surface, a first inner circumferential surface, a second annular radial surface and a second inner circumferential surface connected in sequence from inside to outside and from near to far, wherein the secondary seal abuts against the first annular radial surface relative to the proximal side of the dynamic ring, and the piezoelectric ceramic abuts against the second annular radial surface and the second inner circumferential surface respectively relative to the proximal side and the outer side of the dynamic ring.

6. The online adjustable mechanical sealing device according to claim 2, characterized in that: The piezoelectric ceramic is a ring-shaped piezoelectric ceramic; or the piezoelectric ceramic is a circular arc segment-shaped piezoelectric ceramic, there are multiple circular arc segment-shaped piezoelectric ceramics, and the multiple circular arc segment-shaped piezoelectric ceramics are connected through an arc-shaped support to form a ring structure.

7. The online adjustable mechanical sealing device according to claim 2, characterized in that: The piezoelectric ceramic is tightly arranged on the axial end of the secondary seal.

8. The online adjustable mechanical sealing device according to claim 7, characterized in that: A second annular recessed hole is provided on the stationary ring seat, and the second annular recessed hole is open relative to the axial distal end of the dynamic ring. The piezoelectric ceramic and the secondary seal are arranged in the second annular recessed hole. The piezoelectric ceramic is located on the distal side of the secondary seal relative to the dynamic ring so that the secondary seal abuts against the axial distal end surface of the second annular recessed hole relative to the proximal side of the dynamic ring. The piezoelectric ceramic is limited relative to the distal side of the dynamic ring by a limiting piece provided in the second annular recessed hole.

9. The online adjustable mechanical sealing device according to claim 8, characterized in that: It also includes a retaining ring with a wedge-shaped radial cross section, the retaining ring having a wedge-shaped surface, and the retaining ring is arranged between the piezoelectric ceramic, the inner peripheral wall of the second annular recess and the secondary seal, and the wedge-shaped surface abuts against the secondary seal.

10. The online adjustable mechanical sealing device according to claim 8 or 9, characterized in that: The limiting member is fixed on the inner peripheral wall of the second annular recess.

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