MECHANICAL SEALING DEVICE FOR SEALING LIQUID

Abstract

A mechanical sealing device includes rotating and stationary rings, and rotating and stationary ring adaptors mounted around a rotating shaft. An end surface of the rotating ring adjoins an end surface of the stationary ring by means of springs. The sealing interface includes an adjoining point that is in contact with a liquid medium in an axial section of the device, and an annular peripheral rim surrounding the rotating and stationary rings for agitating the liquid medium. At least a part of the peripheral rim is formed with an inclined surface oriented toward the adjoining point, the inclined surface defining a start point close to the adjoining point and an end point away from the adjoining point in the axial section of the device. The start point is spaced apart from the adjoining point while the end point extends not beyond the adjoining point in the axial direction.

Claims

1. A mechanical sealing device for sealing liquid, the mechanical sealing device being configured to seal a rotating shaft (100) inserting through an equipment enclosure (101) so as to protect a liquid medium existed inside the equipment enclosure (101) from leaking, the mechanical sealing device comprising: rotating and stationary rings (2, 4) and rotating and stationary ring adaptors (1, 5) mounted around the rotating shaft (100), the rotating ring adaptor (1) being fastened to the rotating shaft (100) and supporting the rotating ring (2), the stationary ring adaptor (5) being fastened to the equipment enclosure (101) and supporting the stationary ring (4), and an end surface of the rotating ring (2) adjoining an end surface of the stationary ring (4) by means of springs (6) so as to form a sealing interface (9) perpendicular to an axial direction, the sealing interface (9) comprising an adjoining point (C.sub.1, C.sub.2, C.sub.3, C.sub.4, C.sub.5, C.sub.6, C.sub.7) that is in contact with the liquid medium in an axial section of the device; and an annular peripheral rim (102, 202, 302, 402, 502, 602, 702, 802) surrounding the rotating and stationary rings (2, 4) for agitating the liquid medium, at least a part of the peripheral rim being formed with an inclined surface (102A, 202A, 302A, 402A, 502A, 602A, 702A, 802A) oriented toward the adjoining point, the inclined surface comprising a start point (A.sub.1, A.sub.2, A.sub.3, A.sub.4, A.sub.5, A.sub.6, A.sub.7) close to the adjoining point and an end point (B.sub.1, B.sub.2, B.sub.3, B.sub.4, B.sub.5, B.sub.6, B.sub.7) away from the adjoining point in the axial section of the device, and the start point being spaced apart from the adjoining point while the end point extending not beyond the adjoining point in the axial direction.

2. The mechanical sealing device according to claim 1, wherein: the peripheral rim (102, 202) is integrally formed with one of the rotating and stationary rings (2, 4), such that the one of the rotating and stationary rings (2, 4) has a cross section extending radially beyond the other of the rotating and stationary rings (2, 4) and a part of one of the rotating and stationary rings (2, 4) adjoins the other of the rotating and stationary rings (2, 4).

3. The mechanical sealing device according to claim 1, wherein: the peripheral rim (402, 602, 702) is integrally formed with the rotating ring adaptor (1), and wherein the peripheral rim (402, 602) protrudes from the rotating ring adaptor (1) so as to be placed over an outer peripheral surface of the rotating ring (2), or wherein the peripheral rim (702) protrudes from the rotating ring adaptor (1) and is spaced apart from the rotating ring (2).

4. The mechanical sealing device according to claim 1, wherein: the peripheral rim (302) is integrally formed with the stationary ring adaptor (5) and an outer peripheral surface of the peripheral rim (302) that is away from the adjoining point is configured to abut against an inner wall surface of the equipment enclosure (101).

5. The mechanical sealing device according to claim 1, further comprising: a cylindrical or annular additional component (22) integrally formed with the peripheral rim (502), the additional component (22) being detachably mounted on an end of the rotating ring adaptor (1) that is opposite to the rotating ring (2) in the axial direction, such that a generatrix of an outer peripheral surface of the rotating ring adaptor (1) is parallel with or at an angle with the axial direction.

6. The mechanical sealing device according to claims 1, wherein: the rotating ring (2) has an outer or inner peripheral surface connected to the rotating ring adaptor (1) by means of an O-ring (13, 13′) and the stationary ring has an outer or inner peripheral surface connected to the stationary ring adaptor by means of another O-ring (11, 11′).

7. The mechanical sealing device according to claims 1, wherein: the inclined surface comprises at least one of a straight surface, a curved surface, and a corrugated surface.

8. The mechanical sealing device according to claim 1, wherein: the peripheral rim has an axial section configured to comprise at least one of a tapered shape, a polygonal shape, and an arc shape.

9. The mechanical sealing device according to claim 1, wherein: the peripheral rim (102, 202, 302, 402, 502, 602, 702) is disposed only at the outside of the sealing interface (9), or the peripheral rim (802) is disposed only at the inside of the sealing interface (9).

10. The mechanical sealing device according to claim 1, wherein: the rotating ring (2) is configured as an integral or split structure and the stationary ring (4) is configured as an integral or split structure.

11. The mechanical sealing device for sealing liquid according to claim 1, further comprising: a gland connected to the stationary ring adaptor (5) and a shaft sleeve disposed around the rotating shaft (100), the shaft sleeve (32) being integrally formed with the rotating ring adaptor (1) or being formed as a separate component connected to the rotating ring adaptor (1), so as to package the rotating and stationary rings(2, 4), the rotating and stationary ring adaptors (1, 5) and the springs (6) together, thereby forming a packaged mechanical seal.

12. The mechanical sealing device according to claim 3, further comprising: a cylindrical or annular additional component (22) integrally formed with the peripheral rim (502), the additional component (22) being detachably mounted on an end of the rotating ring adaptor (1) that is opposite to the rotating ring (2) in the axial direction, such that a generatrix of an outer peripheral surface of the rotating ring adaptor (1) is parallel with or at an angle with the axial direction.

13. A mechanical sealing device for accommodating a rotating shaft inserted through an equipment enclosure so as to protect a liquid medium from leaking from said equipment enclosure, said mechanical sealing device comprising: a rotating ring and a stationary ring being mounted around said rotating shaft, wherein a first end surface of said rotating ring is actively biased against a second end surface of said stationary ring, defining thereby a sealing interface that is perpendicular to an axis of rotation of said rotating shaft, said sealing interface defining an adjoining point that is in contact with said liquid medium; an annular peripheral rim defined on one of said rotating ring and said stationary ring for agitating said liquid medium, at least one portion of said peripheral rim being formed with an inclined surface oriented toward said adjoining point, said inclined surface comprising a start point spaced apart from said adjoining point, and an end point; wherein said start point is spaced from said axis of rotation by a first distance, and said end point is spaced from said axis of rotation by a second distance, said second distance being greater than said first distance; and wherein said end point does not extend beyond said adjoining point in said axial direction.

14. A method of protecting a liquid medium from leaking from an equipment enclosure accommodating a rotating shaft, said method comprising the steps of: mounting a rotating ring and a stationary ring around said rotating shaft, wherein a first end surface of said rotating ring is actively biased against a second end surface of said stationary ring, defining thereby a sealing interface that is perpendicular to an axis of rotation of said rotating shaft, said sealing interface defining an adjoining point that is in contact with said liquid medium; defining an annular peripheral rim on one of said rotating ring and said stationary ring for agitating said liquid medium, at least one portion of said peripheral rim being formed with an inclined surface oriented toward said adjoining point, said inclined surface comprising a start point spaced apart from said adjoining point, and an end point; spacing said start point from said axis of rotation by a first distance, and spacing said end point from said axis of rotation by a second distance, said second distance being greater than said first distance; and ensuring that said end point does not extend beyond said adjoining point in said axial direction.

15. A mechanical sealing device for accommodating a rotating shaft having an axis of rotation, said mechanical sealing device comprising: a rotatable ring fixed to and disposed about said rotating shaft; a stationary ring disposed about said rotating shaft, said rotatable ring and said stationary ring abutting one another at a contact point; a peripheral rim formed on one of said rotatable ring and said stationary ring, said peripheral rim defining an inclined surface having a start point and an end point; and wherein said start point is spaced away from said contact point at a first distance from said axis of rotation, and said end point is spaced away from said contact point at a second distance from said axis of rotation, said second distance being greater than said first distance; and wherein said end point does not extend beyond a plane perpendicular to said axis of rotation and containing said contact point.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and, together with the description thereof, serve to explain the principles of the disclosure.

[0027] FIG. 1 is a view in axial section of a mechanical sealing device for sealing liquid mounted on rotating equipment according to an embodiment of the present application;

[0028] FIG. 2 is a detailed view in axial section of stationary and rotating rings of the mechanical sealing device in FIG. 1;

[0029] FIG. 3 is a view in axial section of a mechanical sealing device for sealing liquid mounted on rotating equipment according to another embodiment of the present application;

[0030] FIG. 4 is a detailed view in axial section of stationary and rotating rings of the mechanical sealing device in FIG. 3;

[0031] FIG. 5 is a view in axial section of a mechanical sealing device for sealing liquid mounted on rotating equipment according to another embodiment of the present application;

[0032] FIG. 6 is a view in axial section of a mechanical sealing device for sealing liquid mounted on rotating equipment according to another embodiment of the present application;

[0033] FIG. 7 is a view in axial section of a mechanical sealing device for sealing liquid mounted on rotating equipment according to another embodiment of the present application;

[0034] FIG. 8 is a view in axial section of a mechanical sealing device for sealing liquid mounted on rotating equipment according to another embodiment of the present application; and

[0035] FIG. 9 is a view in axial section of a mechanical sealing device for sealing liquid mounted on rotating equipment according to another embodiment of the present application.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0036] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the drawings. It should be noted that the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless it is specifically stated otherwise.

[0037] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses.

[0038] In all of the examples illustrated and discussed herein, any specific values should be interpreted to be illustrative only and non-limiting. Thus, other examples of the exemplary embodiments could have different values.

[0039] Notice that similar reference numerals and letters refer to similar items in the following figures, and thus once an item is defined in one figure, it is possible that it need not be further discussed for following figures.

[0040] Hereinafter, a mechanical sealing device for sealing liquid provided by the present application is referred to as a sealing device. The exemplary sealing device is suitable for using in rotating equipment such as a pump. The rotating equipment comprises an equipment enclosure 101 and a rotating shaft 100 inserting through the equipment enclosure 101, such that the rotating shaft 100 is at least partially placed in the equipment enclosure 101. In view of this, the term “axial direction” refers to a direction along an axis L of the rotating shaft 100, the term “axial section” refers to a vertical plane containing the axis L, the term “end surface” refers to an area from a plane perpendicular to the axis L, the term “front” refers to a direction running further into the equipment enclosure 101 in the axial direction, i.e., a left hand side in each figure, the term “rear” refers to a direction running away from the equipment enclosure 101 in the axial direction, i.e., a right hand side in each figure, the term “inner” refers to a direction approaching the axis L in a radial direction, and the term “outer” refers to a direction away from the axis L in the radial direction.

[0041] Generally, each of the exemplary sealing devices shown in FIGS. 1 to 9 comprises a plurality of components assembled together, and the plurality of components cooperate with each other to seal the rotating shaft 100 with respect to the equipment enclosure 101, thereby preventing a liquid medium existed inside the equipment enclosure 101 from leaking. Moreover, the exemplary sealing devices may be configured as a packaged-type sealing device or a separated-type sealing device.

[0042] The plurality of components may comprise a rotating ring assembly fixed to and rotating with the rotating shaft 100 and a stationary ring assembly fixed to and keeping stationary with the equipment enclosure 101.

[0043] The rotating ring assembly comprises a rotating ring adaptor 1 and a rotating ring 2 supported by the rotating ring adaptor 1. The rotating ring 2 is circumferentially fixed relative to the rotating ring adaptor 1 by means of a plurality of pins 3.

[0044] The stationary ring assembly comprises a stationary ring adaptor 5 and a stationary ring 4 supported by the stationary ring adaptor 5. The stationary ring adaptor 5 is provided with a plurality of springs 6 for pushing the stationary ring 4 forward, and the stationary ring 4 is circumferentially fixed relative to the stationary ring adaptor 5 by means of a plurality of pins 8. The plurality of springs 6 pushes the stationary ring 4 forward against the rotating ring 2, such that a certain axial pressure is applied to the rotating and stationary rings 2, 4, while allowing the rotating ring 2 to rotate relative to the stationary ring 4. In the present application, the plurality of springs 6 can preferably be configured as small cylindrical springs or replaced by bellows.

[0045] The stationary ring adaptor 5 can be fastened to a rear wall surface of the equipment enclosure 101 by a plurality of bolts 7 to cover a hole of the equipment enclosure 101 through which the rotating shaft 100 passes. Thus, in the present application, the stationary ring adaptor 5 is also functioned as a gland as well known in the prior art. Additionally or alternatively, the sealing device may comprise a gland connected to the stationary ring adaptor 5, the gland being fastened to the rear wall surface of the equipment enclosure 101 by the plurality of bolts 7 to cover the hole of the equipment enclosure 101 through which the rotating shaft 100 passes.

[0046] One or both of the rotating and stationary rings 2, 4 may have an integral or split structure, that is, comprise a pair of semi-annular halves, the pair of halves being assembled to each other for forming a complete sealing ring around the rotating shaft 100. Split or joint surfaces of the pair of halves may be provided with matching structures, such as convex and concave structures, respectively, so as to facilitate maintaining a connection state of the pair of halves. Moreover, a split line of the pair of halves is perpendicular to the axial direction.

[0047] If both of the rotating and stationary rings 2, 4 are split, the split line of the pair of halves of the rotating ring 2 need to be circumferentially offset from the split line of the pair of halves of the stationary ring 4.

[0048] In the present application, for easy replacement of the rotating and stationary rings 2, 4, it is preferable that both of the rotating and stationary rings 2, 4 are split. However, it is within the scope of the present application that only one of the rotating and stationary rings 2, 4 is split, especially the one that is prone to be worn.

[0049] Material of the rotating and stationary rings 2, 4 may be any one of plastic, ceramic, for example, silicon carbide, graphite, and metal alloy, for example, tungsten carbide. Material of the rotating and stationary ring adaptors 1, 5 may be metal alloy, for example, 316 stainless steel or 304 stainless steel.

[0050] Described below are designed peripheral rims provided by the embodiments of the present application. It is noted that the embodiments can be combined or used separately according to a specific application.

[0051] In the embodiment as seen in FIG. 1 and detailed in FIG. 2, a peripheral rim 102 is integrally formed with the stationary ring 4 and disposed adjacent to the sealing interface 9. Specifically, the stationary ring adaptor 5 may be provided with a plurality of axial holes into which the plurality of springs 6 can be placed and an annular groove 14 in communication with the plurality of axial holes, and a rear end of the stationary ring 4 is received in the annular groove 14 so as to be pushed forward by the plurality of springs 6. Thus, an end surface formed by a front end of the stationary ring 4 adjoins an end surface of the rotating ring 2 so as to form a sealing interface 9 that is perpendicular to the axial direction. The sealing interface 9 comprises an adjoining point C.sub.1 in contact with the liquid medium in an axial section of the device. Moreover, the rear end of the stationary ring 4 has an inner peripheral surface connected to the stationary ring adaptor 5 via an O-ring 11.

[0052] Starting from the front end of the stationary ring 4, the peripheral rim 102 extends radially away from the sealing interface 9 as it axially approaches the sealing interface 9 so as to surround the rotating and stationary rings 2, 4. Thus, the stationary ring 4 integrally formed with the peripheral rim 102 has a cross section extending radially beyond the rotating ring 2 and the rotating ring adaptor 1, and in which case a part of one of the rotating and stationary rings 2, 4 adjoins the other of the rotating and stationary rings 2, 4.

[0053] As shown in FIGS. 1 and 2, the peripheral rim 102 has an axial section configured to comprise a tapered shape, but it can be understood that the peripheral rim 102 can have an axial section configured to comprise at least one of a tapered shape, a polygonal shape (for example, a triangle shape, a rectangle shape, a pentagonal shape, etc.), an arc shape, and the like, such that compared to the rotating ring 2 and the rotating ring adaptor 1, the peripheral rim 102 protrudes radially further into the liquid medium. Thus, the peripheral rim 102 can act to agitate the liquid medium flowing in the vicinity of the sealing interface 9 for forming a turbulent flow, thereby causing changes in the temperature, flow rate and pressure of the liquid medium. As such, impurities, especially hard particles in the liquid medium can't be deposited when the liquid medium moves chaotically.

[0054] At least a part of the peripheral rim 102 is formed with an inclined surface 102A oriented toward the adjoining point C.sub.1, and the impurities in the agitated a liquid medium are discharged along the inclined surface 102A so as to move away from the sealing interface 9 due to a centrifugal force. The centrifugal force is generated by a rotation of the rotating shaft 100.

[0055] For example, as show in FIG. 2, the inclined surface 102A comprises a start point A.sub.1 close to an adjoining point C.sub.1 and an end point B.sub.1 away from the adjoining point C.sub.1 in the axial section of the device. The start point A.sub.1 is spaced apart from the adjoining point C.sub.1. The end point B.sub.1 does not extend axially beyond the adjoining point C.sub.1. The end point B.sub.1 is the highest point of an axial section protruding into the liquid medium. A line connecting the start point A.sub.1 to the end point B.sub.1 is inclined toward the adjoining point C.sub.1. Another line connecting the start point A.sub.1 to the adjoining point C.sub.1 is bent.

[0056] The inclined surface 102A may be configured to comprise at least one of a straight surface, a curved surface, a corrugated surface, and the like.

[0057] Additionally or alternatively, a plurality of protrusions are densely distributed on the inclined surface 102A so as to increase a frictional force between the impurities and the inclined surface 102A, such that the impurities are more likely to adhere to the inclined surface 102A by means of the frictional force and to be discharged quickly along the inclined surface 102A.

[0058] It is necessary for both of the end surfaces of the rotating and stationary rings 2, 4 to meet a relatively high roughness requirement, so as to achieve a “mirror finish” for reducing a frictional force between the rotating and stationary rings 2, 4 when the rotating ring 2 is rotating. Thus, it is in the process of machining to grind the end surfaces of the rotating and stationary rings 2, 4 separately. In FIG. 1, the peripheral rim 102 integrally formed with the stationary ring 4 does not extend axially beyond the sealing interface 9, such that a tool used to grind the end surface of the stationary ring 4 will not be affected by the peripheral rim 102 integrally formed with the stationary ring 4.

[0059] It can be seen in FIG. 1 that the rotating ring adaptor 1 comprises a front portion with a first outer diameter and a rear portion with a second outer diameter. The first outer diameter is larger than the second outer diameter. The exemplary sealing device further comprises a shaft sleeve 32 with a third outer diameter. The second outer diameter is larger than the third outer diameter. The shaft sleeve 32 extends rearward, and the shaft sleeve 32 is integrally formed with the rotating ring adaptor 1 or connected to the rotating ring adaptor 1 as a separate component, so as to package the rotating and stationary ring adaptors 1, 5, the rotating and stationary rings 2, 4, and the spring 6 together, thereby forming a packaged mechanical seal

[0060] The front portion of the rotating ring adaptor 1 has an inner peripheral surface connected to the rotating shaft 100 via an O-ring 12

[0061] The rotating ring adaptor 1 forms a stepped surface for placing the rotating ring 2 as a result of a difference between the first and second outer diameters and a difference between the second and third outer diameters. Correspondingly, the rotating ring 2 is shaped to be complementary to the stepped surface. That is, the rotating ring 2 comprises a front portion with a first inner diameter and a rear portion with a second inner diameter. The first inner diameter is larger than the second inner diameter. The front portion of the rotating ring 2 has an inner peripheral surface connected to the rear portion of the rotating ring adaptor 1 by means of another O-ring 13. The O-rings 12 and 13 facilitate heat dissipation of the rotating ring 2.

[0062] In the packaged mechanical seal, the rotating ring assembly is fitted with the stationary ring assembly in advance. Thus, the shaft sleeve 32 extends through the stationary ring adaptor 5 for reaching the outside of the equipment enclosure 101 and forms a clearance fit with an inner peripheral surface of the stationary ring adaptor 5 so as not to block the rotating ring assembly from rotating with the rotating shaft 100.

[0063] A locking ring 15 is mounted around the shaft sleeve 32 at the outside of the equipment enclosure 101 so as to cooperate with a plurality of positioning blocks 16 (usually three) to position the rotating ring assembly relative to the stationary ring assembly in the axial and radial directions. The plurality of positioning blocks 16 are fastened to a rear end surface of the stationary ring adaptor 5 by means of a plurality of bolts 17. Then, the rotating shaft 100 is inserted through the packaged rotating and stationary ring assemblies, and one or more screws (not shown) can be screwed into the locking ring 15 in the radial direction and pass through the shaft sleeve 32, thereby fastening the packaged rotating and stationary ring assemblies to the rotating shaft 100. Before the rotating shaft 100 starts to be operated, the plurality of positioning blocks 16 shall be removed from the rear end surface of the stationary ring adaptor 5.

[0064] Optionally, a part of the rotating ring 2 close to the sealing interface 9 forms an inclined chamfer 103 that is inclined away from the sealing interface 9, that is, the inclined chamfer 103 is inclined upward and forward and has a degree of inclination approximately equal to a degree of inclination of the line connecting the start point A.sub.1 to the end point B.sub.1, thereby forming a uniform oblique space that is favorable for the impurities to leave the sealing interface 9. As such, outer peripheral surfaces of the rotating and stationary rings 2, 4 are set to be substantially flush with each other. Nevertheless, the stationary ring 4 is shortened in diameter for forming an end of the sealing interface that is in contact with air, such that the sealing interface 9 has a reduced area to reduce the frictional force between the rotating ring 2 and the stationary ring 4 when the rotating ring 2 is rotating.

[0065] The stationary ring adaptor 5 may also be provided with a rinse passage 19. Since there is a gap between the outer peripheral surface of the stationary ring 4 and an outer peripheral surface of the annular groove 14, one end of the rinse passage 19 can be fluidly connected to the inside of the equipment enclosure via the gap. When necessary, rinse water free of the impurities can be fed into the other end of the rinse passage 19 for rinsing the sealing device. If the rotating equipment is operated, the rinse water shall have a pressure greater than the liquid medium existed inside the equipment enclosure.

[0066] The embodiment as seen in FIG. 3 and detailed in FIG. 4 is different from the embodiment as seen in FIG. 1 and detailed in FIG. 2 in that a peripheral rim 202 is integrally formed with the rotating ring 2. The peripheral rim 202 extends radially away from the sealing interface 9 as it approaches the sealing interface 9. The rotating ring 2 integrally formed with the peripheral rim 202 has an axial section extending radially beyond the stationary ring 4, and in which case a part of one of the rotating and stationary rings 2, 4 adjoins the other of the rotating and stationary rings 2, 4.

[0067] In FIG. 4, a start point A.sub.2 of an inclined surface 202A is spaced apart from an adjoining point C.sub.2 while an end point B.sub.2 does not extend axially beyond the adjoining point C.sub.2. The end point B.sub.2 is the highest point of an axial section protruding into the liquid medium. A line connecting the start point A.sub.2 to the end point B.sub.2 is inclined toward the adjoining point C.sub.2. Another line connecting the start point A.sub.2 to the adjoining point C.sub.2 is configured as an arc line. Thus, a tool can be used to grind the end surface of the rotating ring 2 in the machining process without taking the the peripheral rim 202 integrally formed with the rotating ring 2 into consideration.

[0068] In the case where the peripheral rim 202 is integrally formed with the rotating ring 2, a part of the stationary ring 4 that is adjacent to the sealing interface 9 forms an inclined chamfer 203 that is inclined away from the sealing interface 9, that is, the inclined chamfer 203 is inclined upward and rearward and has a degree of inclination approximately equal to a degree of inclination of the inclined surface 202A, thereby forming a uniform oblique space that is favorable for the impurities to leave the sealing interface 9.

[0069] A peripheral rim can be integrally formed with the stationary ring adaptor 5 instead of or in addition to the peripheral rim integrally formed with the rotating or stationary ring 2, 4. Specifically, as shown in FIG. 1, starting from a front end surface of the stationary ring adaptor 5, the peripheral rim 302 extends radially away from the sealing interface 9 as it axially approaches the sealing interface 9. At least a part of the peripheral rim 302 that is adjacent to the sealing interface 9 is formed with an inclined surface 302A oriented toward the sealing interface 9, while an outer peripheral surface of the peripheral rim 302 that is away from the sealing interface 9 is abutted against an inner wall surface perpendicular to the rear wall surface of the equipment enclosure 101. The peripheral rim 302 of the stationary ring adaptor 5 can further agitate the impurities in the flowing liquid medium and facilitate correct positioning of the stationary ring adaptor 5 relative to the equipment enclosure 101 when the stationary ring adaptor 5 is mounted to the equipment enclosure 101.

[0070] In the embodiment as shown in FIG. 5, a peripheral rim 402 is integrally formed with the rotating ring adaptor 1 and is disposed adjacent to the sealing interface 9. Both of the rotating ring adaptor 1 and the rotating ring 2 have a different shaped axial section in the embodiment as shown in FIG. 5 as compared to the embodiments as shown in FIGS. 1 to 4. That is, the rotating ring adaptor 1 integrally formed with peripheral rim 402 has front and rear portions with a diameter incrementally increasing from front to rear so as to form a truncated cone. The rear portion of the rotating ring adaptor 1 is provided with an annular groove 21 for receiving a front portion of the rotating ring 2. Correspondingly, a rear portion of the rotating ring 2 has an outer diameter larger than the front portion of the rotating ring 2, such that the rotating ring 2 is complementary to the rotating ring adaptor 1. The front portion of the rotating ring 2 has an outer peripheral surface connected with the rotating ring adaptor 1 by means of an O-ring 13′.

[0071] Starting from the outer peripheral surface of the rotating ring adaptor 1, the peripheral rim 402 extends radially away from the sealing interface 9 as it axially approaches the sealing interface 9, such that at least a part of the peripheral rim 402 is placed over the rear portion of the rotating ring 2, thereby forming an inclined surface 402A oriented toward the sealing interface 9. A start point A.sub.3 of the inclined surface 402A is spaced apart from an adjoining point C.sub.3 while an end point B.sub.3 does not extend axially beyond the adjoining point C.sub.3. The end point B.sub.3 is the highest point of an axial section protruding into the liquid medium. An outer peripheral surface of the peripheral rim 402 that is facing away from the sealing interface 9 forms a surface inclined rearward and upward along the entire rotating ring adaptor 1. The peripheral rim 402 of the rotating ring adaptor 1 does not extend axially beyond the sealing interface 9, such that the sealing device can be configured as a compact structure especially in the axial direction.

[0072] Different from the embodiment of FIG. 5, there is provided in the embodiment of FIG. 6 a cylindrical or annular additional component 22 detachably mounted on an end of the rotating ring adaptor 1 that is axially opposite to the other end of the rotating ring adaptor 1 for supporting the rotating ring 2. For example, a plurality of fastening screws 23 are screwed through the additional component 22 and into the front portion of the rotating ring adaptor 1 in the axial direction, thereby fastening the additional component 22 to the front portion of the rotating ring adaptor 1. Optionally, the front portion of the rotating ring adaptor 1 is provided with an additional stepped part, such that the additional component 22 can be placed over the additional stepped part of the rotating ring adaptor 1. The additional component 22 is configured as a customized component for being integrally formed with a peripheral rim 502 and to be replaced easily. As such, an original structure of the rotating ring adaptor 1 is less likely to be modified excessively with the presence of the additional component 22. In FIG. 6, the peripheral rim 502 is spaced apart from the rotating ring 2. Obviously, a start point A.sub.4 of an inclined surface 502A is spaced apart from an adjoining point C.sub.4 while an end point B.sub.4 of the inclined surface 502A does not extend axially beyond the adjoining point C.sub.4. The end point B.sub.4 is the highest point of the axial section protruding into the liquid medium. In this case, the generatrix of the outer peripheral surface of the rotating ring adaptor 1 is parallel to or at an angle with the axial direction.

[0073] In the two embodiments of FIGS. 7 and 8 in which peripheral rims 602 and 702 are integrally formed with the rotating ring adaptor 1, there are provided a plurality of fastening screws, instead of the locking ring 15, configured to fasten the rotating ring adaptor 1 to the rotating shaft 100. The plurality of fastening screws are screwed through the front portion of the rotating ring adaptor 1 and into the rotating shaft 100 in the radial direction so as to fasten the rotating ring adaptor 1 to the rotating shaft 100. That is, the exemplary sealing devices of FIGS. 7 and 8 are configured as a separated-type sealing device, in which cases the peripheral rims 602 and 702 can also be designed. As shown in FIG. 7, the peripheral rim 602 is designed to protrude from the rotating ring adaptor 1 so as to be placed over the outer peripheral surface of the rotating ring 2, such that a start point A.sub.5 of an inclined surface 502A is spaced apart from an adjoining point C.sub.5 while an end point B.sub.5 of the inclined surface 502A does not extend axially beyond the adjoining point C.sub.5. As shown in FIG. 8, the peripheral rim 702 is designed to protrude from the rotating ring adaptor 1 so as to be spaced apart from the rotating ring 2, such that a start point A.sub.6 of an inclined surface 702A is spaced apart from an adjoining point C.sub.6 while an end point B.sub.6 does not extend axially beyond the adjoining point C.sub.6. Thus, the peripheral rims can be designed flexibly according to a specific application.

[0074] The peripheral rim integrally formed with the rotating ring 2 and/or the rotating ring adaptor 1 also serves as a barrier to at least partially block the impurities in the flowing liquid medium from approaching the sealing interface 9.

[0075] In each of the embodiments of FIGS. 1 to 4, the inner peripheral surface of the rear end of the stationary ring 4 is connected to the stationary ring adaptor 5 by means of an O-ring 11, and another O-ring 20 is provided between the front end surface of the stationary ring adaptor 5 and the rear wall surface of the equipment enclosure 101. By contrast, in each of the embodiments of FIGS. 5 to 8, the outer peripheral surface of the rear end of the stationary ring 4 is connected to the stationary ring adaptor 5 by means of an O-ring 11′, and a gasket 20′ is provided between the front end surface of the stationary ring adaptor 5 and the rear wall surface of the equipment enclosure 101. These are only examples of the components other than the peripheral rim of the sealing device in related to various configurations of the sealing device.

[0076] In each of the embodiments of FIGS. 1 to 8, an area in the equipment enclosure 101 configured for storing the liquid medium is at least partially bounded by the outer peripheral surfaces of the rotating and stationary rings 2, 4 and the front portion of the rotating ring adaptor 1, while in the embodiment of FIG. 9, the rotating ring assembly becomes located outside the equipment enclosure 101, such that an area in the equipment enclosure 101 configured for storing the liquid medium is at least partially bounded by inner peripheral surfaces of the rotating and stationary rings 2, 4 and the stationary ring adaptor 5, in which case the peripheral rim 802 is integrally formed with one of the rotating and stationary rings 2, 4.

[0077] In the embodiments of FIGS. 1 to 8, the peripheral rims 102, 202, 302, 402, 502, 602, and 702 are disposed only at the outside of the sealing interface 9, that is, the peripheral rims 102, 202, 302, 402, 502, 602, and 702 protrude radially away from the rotating shaft 100. In the embodiment of FIG. 9, the peripheral rim 802 is disposed only at the inside of the sealing interface 9, that is, the peripheral rim 802 protrudes radially inward relative to the rotating shaft 100. At least a part of the peripheral rim 802 is formed with an inclined surface 802A oriented toward an adjoining point C.sub.7. The inclined surface 802A comprises a start point A.sub.7 close to the adjoining point C.sub.7 and an end point B.sub.7 away from the adjoining point C.sub.7 in an axial section of the device. The start point A.sub.7 is spaced apart from the adjoining point C.sub.7 while the end point B.sub.7 does not extend axially beyond the adjoining point C.sub.7. The end point B.sub.7 is the highest point of an axial section protruding into the liquid medium.

[0078] Although some specific embodiments of the present disclosure have been demonstrated in detail with examples, it should be understood by a person skilled in the art that the above examples are only intended to be illustrative but not to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments could be modified without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.