CN218718782U - End face seal assembly - Google Patents

Abstract

The utility model discloses an end face seal assembly, end face seal assembly includes: a first seal ring formed with a first end face; the second sealing ring is provided with a second end face opposite to the first end face, and a sealing gap is formed between the first end face and the second end face; wherein a circumferential groove is formed in at least one of the first end face and the second end face, the circumferential groove being located between the high pressure side and the low pressure side to control a potential location of a phase change of the fluid in the seal gap. According to the utility model discloses an end face seal assembly can improve the pressure distribution in the seal clearance, and the potential position of control fluid phase transition enlarges lubricated region, even take place the phase transition, can effectively reduce wear, is showing the life who improves end face seal assembly.

Description

End face seal assembly

Technical Field

The utility model belongs to the technical field of the mechanical seal technique and specifically relates to a face seal subassembly is related to.

Background

The mechanical seal face structure is a key component of the foundation in various rotary fluid machines. The mechanical seal is a device which keeps the seal rings in contact with each other and relatively slides under the combined action of end face fluid pressure perpendicular to the rotation axis, the action of the compensation element and the auxiliary seal, and is less in fluid leakage. The common mechanical end face seal has a relatively mature sealing end face and structure design for sealing a gas medium and a liquid medium. With the development of sealing technology and the extension of sealing application media, related designs also have shortcomings and gaps for media applications where phase changes may occur on both sides of the seal due to differences in pressure and temperature. Such application scenarios are basically that the medium is kept in a liquid state in a sealed cavity under certain conditions of temperature and pressure, and changes to a vapor phase under conditions outside the seal. Therefore, phase changes usually occur on the sealing end face, and if the phase changes are not controlled by a targeted design, the sealing cannot work effectively or even fails or accidents occur if the media completely change the phase in the sealing gap. In this case, it is more common to have a contact-type mechanical face seal, the face of which is not provided with any groove-type, substantially flat face. The design has the disadvantages that the abrasion of the sealing end surface is large, the service life is relatively short, so that the end surface of some non-contact end surface sealing adopts the design of locally arranging the shallow grooves, and the mechanical sealing utilizing the fluid dynamic pressure effect is usually provided with the dynamic pressure shallow grooves according to the rotating direction of the end surface, such as the spiral shallow grooves with the depth of several microns to dozens of microns, so that the advantages of the friction abrasion improvement and the leakage rate control can be considered. However, most of the conventional dynamic pressure grooves have directionality, and in the case of considering the rotating direction, even in the case of low speed, the advantages of the dynamic pressure grooves are reduced, and the seal may fail in the case of medium phase change. Meanwhile, the machining cost of shallow grooves capable of providing dynamic pressure is often high. The present application is directed to a face seal assembly to address the above-mentioned problems.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, an object of the utility model is to provide an end face seal assembly can improve the pressure distribution in the sealed clearance, and the potential position of control fluid phase transition enlarges lubricated region, even take place the phase transition, can effectively reduce wear, is showing the life who improves end face seal assembly.

According to the utility model discloses an end face seal assembly, include: a first seal ring formed with a first end face; the second sealing ring is provided with a second end face opposite to the first end face, and a sealing gap is formed between the first end face and the second end face; at least one of the first end face and the second end face is provided with a circumferential groove, and the circumferential groove is located between the high-pressure side and the low-pressure side to control the position of fluid phase change in the sealing gap.

The utility model relates to an end face seal subassembly, fluid flows in behind the seal clearance by high pressure side direction low pressure side, pressure in the seal clearance is along radially reducing gradually, owing to be equipped with the circumference groove on at least one of first terminal surface and second terminal surface, fluid is behind the circumference groove of flowing into, pressure stops reducing, make fluid pressure stabilize at a scope, thereby make end face seal subassembly possess the ability that the fluid pressure in the control seal clearance is higher than the saturated vapor pressure of fluid, and then the potential position that the control phase transition takes place, enlarge lubricated region, effective reducing wear, show the life who improves end face seal subassembly.

According to some embodiments of the invention, at least one of the first end face and the second end face is provided with a radial groove extending from the high pressure side to the low pressure side.

According to some embodiments of the present invention, the radial groove is configured to be plural, and the radial groove is arranged at intervals in a circumferential direction of the first end surface and/or the second end surface.

According to some embodiments of the invention, the radial groove comprises: a plurality of first radial grooves configured adjacent to a high pressure side, the plurality of first radial grooves being circumferentially spaced apart; a plurality of second radial grooves configured to be adjacent to a low pressure side, the plurality of second radial grooves being arranged at intervals in a circumferential direction, the first radial grooves being arranged to be staggered in the circumferential direction with respect to the second radial grooves.

According to some embodiments of the invention, the side wall of the circumferential groove adjacent to the low pressure side communicates with one end of each of the first radial grooves adjacent to the high pressure side.

According to some embodiments of the invention, the circumferential groove comprises a plurality of circumferentially spaced connecting sections, each communicating with one or more first radial grooves.

According to some embodiments of the invention, the circumferential groove is configured in plurality and comprises: a first circumferential groove disposed adjacent the high pressure side and in communication with each of the first radial grooves; a second circumferential groove disposed adjacent the low pressure side and in communication with each of the second radial grooves.

According to some embodiments of the invention, the inner wall surfaces of the circumferential groove and the radial groove are configured as a plane or a curved surface.

According to the utility model discloses a some embodiments, the degree of depth in circumferential groove is d1, the degree of depth in radial groove is d2, and satisfies: d1 is more than or equal to 0.05mm and less than or equal to 2mm, and d2 is more than or equal to 0.05mm and less than or equal to 2mm.

According to some embodiments of the present invention, the width of the circumferential groove is D1, the width of the radial groove is D2, and satisfies: d1 is more than or equal to 0.1mm and less than or equal to 2mm, and D2 is more than or equal to 0.1mm and less than or equal to 2mm.

According to some embodiments of the invention, the circumferential groove is configured as a plurality of wave segments, broken line segments or curves that are continuous in the circumferential direction.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic structural view of an end face seal assembly according to an embodiment of the present invention;

fig. 2 is a schematic structural view of an end face seal assembly according to another embodiment of the present invention;

FIG. 3 is a schematic structural view of an end face seal assembly according to another embodiment of the present invention;

FIG. 4 is a schematic structural view of an end face seal assembly according to another embodiment of the present invention;

FIG. 5 is a schematic plan view of circumferential and radial slots of an embodiment of the present invention;

fig. 6 is a schematic plan view of circumferential and radial grooves of another embodiment of the present invention;

fig. 7 is a schematic plan view of circumferential and radial slots of another embodiment of the present invention;

fig. 8 is a schematic plan view of circumferential and radial grooves of another embodiment of the present invention;

fig. 9 is a schematic plan view of circumferential and radial slots of another embodiment of the present invention;

fig. 10 is a schematic view of the end face seal assembly of one embodiment of the present invention showing the result of local deformation of the end face.

Reference numerals:

1: a shaft; 2: a housing; 3: a first seal ring; 4: a second seal ring; 5: a first radial slot; 6: a first circumferential groove; 7: a second radial slot; 8: a second circumferential groove.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature. An end face seal assembly according to an embodiment of the present invention is described below with reference to fig. 1-10.

For medium application in which phase change may occur at two sides of the seal due to different pressures and temperatures, a contact type mechanical end face seal is more common, most of the end faces are not provided with any groove type and are basically flat end faces, and the seal mode has the advantages of large abrasion of the seal end faces and relatively short service life. The end face of some non-contact end face seals adopts a design of locally arranging shallow grooves, the mechanical seal utilizing the fluid dynamic pressure effect is often provided with dynamic pressure shallow grooves according to the rotation direction of the end face, the traditional dynamic pressure grooves mostly have directionality, the advantage of the dynamic pressure grooves can be reduced under the condition that the rotation direction needs to be considered or the low speed is required, the seal can also fail along with the medium phase change, and meanwhile, the processing cost for manufacturing the shallow grooves is also higher. The present application is directed to an end face seal assembly to address the above technical problems to some extent.

An end face seal assembly according to an embodiment of the present invention is described below with reference to fig. 1-10.

According to the utility model discloses an end face seal assembly, refer to fig. 1, end face seal assembly includes first sealing ring 3 and second sealing ring 4, and first sealing ring 3 is formed with the first terminal surface, and second sealing ring 4 is formed with the second terminal surface just to first terminal surface, forms the seal clearance between first terminal surface and the second terminal surface, and it needs to be said that fluid flows to the low pressure side from the high pressure side in the seal clearance; at least one of the first end face and the second end face is provided with a circumferential groove, and the circumferential groove is located between the high-pressure side H and the low-pressure side L to control potential positions of fluid phase change in the sealing clearance.

It is known to the person skilled in the art that for a fluid flowing in the sealing gap there will be an on-way pressure decrease in the direction of flow, the degree of pressure decrease being inversely proportional to the dimension of the sealing gap, the greater the dimension of the sealing gap, the smaller the degree of pressure decrease. The utility model provides an end face seal assembly, owing to be formed with the circumference groove on at least one in first terminal surface and second terminal surface, the circumference groove can be constructed to the ring channel that encircles 3 rotation centers of first sealing ring or 4 rotation centers of second sealing ring, the fluid flows in the seal clearance to low pressure side L by high pressure side H, pressure in the clearance also radially reduces thereupon, after fluid inflow circumference groove, the fluid circulation route widens, sealed terminal surface loss of pressure reduces greatly, fluid stops to reduce after flowing into the circumference groove promptly pressure, make fluid pressure stabilize on the saturated vapour pressure of liquid. Therefore, according to the design of different media and working conditions, the phase change between the inner radius of the circumferential groove and the outer radius of the end face opposite to the first sealing ring 3 and the second sealing ring 4 can be avoided as much as possible, the potential position of the phase change is further controlled, the vaporization position is limited in a limited area, and here, it is required to be noted that if the phase change occurs in the sealing gap, the occupied area proportion of a vapor phase is larger, the viscosity of gas is far smaller than that of liquid, the large-area vaporization area is not beneficial to sealing and keeping the working state, the vaporization position is limited in the limited area, namely, the lubrication area is enlarged, the abrasion caused by contact between the first end face and the second end face is effectively reduced, and the service life of the end face sealing assembly is obviously prolonged.

According to some embodiments of the utility model, when the end face seal subassembly is used for the rotating machinery to seal, the rotating machinery further includes axle 1 and casing 2, 2 bottom trompils of casing, the axle 1 of rotating machinery is worn out from the hole, the first sealing ring 3 of fixed connection on the casing 2, first sealing ring 3 is formed with first terminal surface, second sealing ring 4 is connected on axle 1 and can rotate around axle 1, second sealing ring 4 is formed with the second terminal surface, the first terminal surface of first sealing ring 3 is just to laminating with the second terminal surface of second sealing ring 4. It should be noted here that the operation states of the first seal ring 3 and the second seal ring 4 are not particularly limited, and the second seal ring may also be fixedly connected to the housing 2, the first seal ring 3 rotates around the shaft 1, a high pressure region is formed outside the first seal ring 3 and the second seal ring 4 in the housing 2, a low pressure region is formed between the shaft body and the first seal ring 3 and the second seal ring 4, and a medium in the high pressure region in the housing 2 may enter the low pressure region through the seal gap to lubricate when the first seal ring 3 and the second seal ring 4 rotate relatively, and to improve the bearing capacity between the first seal ring 3 and the second seal ring 4.

According to some embodiments of the present invention, the number and positions of the circumferential grooves are not particularly limited, and the circumferential grooves may be formed only on the first seal ring 3, or only on the second seal ring 4, or both the first seal ring 3 and the second seal ring 4.

According to some embodiments of the invention, at least one of the first end surface and the second end surface is provided with a radial groove extending from the high pressure side to the low pressure side. Specifically, the radial grooves may be provided only on the first end face, only on the second end face, or both the first end face and the second end face. Therefore, the pressure of the fluid stops reducing after flowing into the circumferential groove, the radial groove can further stabilize the fluid pressure in a wider range, the phenomenon that the fluid pressure is reduced to the saturated vapor pressure of the liquid to cause phase change is avoided, the pressure of the fluid in the sealing gap is further controlled to be reduced, meanwhile, the actual end face specific pressure of the seal is reduced, and the bearing capacity of the seal is further improved.

It should be noted here that the bearing capacity includes two parts, which are the integral of the pressure distribution of the fluid in the gap and the contact force when the solid contacts, and the end face specific pressure refers to the ratio of the contact force of the solid to the bearing capacity of the seal. Because the radial groove can stabilize the fluid pressure in a wider range and avoid the reduction of the fluid pressure to a certain extent, the integral area of the pressure distribution of the fluid in the sealing gap can be increased, which is equivalent to the increase of the sealing bearing capacity, namely the reduction of the end face specific pressure.

The technical personnel in the field know that, when the face seal assembly is used for rotary mechanical seal, it is lower to open and stop stage speed, be provided with circumference groove and radial groove simultaneously on the face seal assembly, under the circumstances of not changeing, the terminal surface specific pressure also can be very little, also has certain bearing capacity, so can open the stage protection terminal surface at sealed opening through setting up radial groove, avoid the friction, through the design of parameterization, make the face seal assembly when carrying out effective control to the leakage rate, be applicable to the various rotational speeds of low well high. Meanwhile, due to the symmetrical design of the circumferential groove and the radial groove, the end face sealing assembly can be suitable for various rotating directions and is not limited by a single rotating direction.

In some embodiments, the radial groove is configured as a connecting groove extending radially along the first seal ring 3 or the second seal ring 4, the radial groove extending in a direction passing through a center of rotation of the first seal ring 3 or the second seal ring 4.

According to some embodiments of the present invention, the positions of the radial groove and the circumferential groove on the sealing ring are not particularly limited, for example, referring to fig. 1, both the radial groove and the circumferential groove may be provided on the second sealing ring 4; referring to fig. 2, both radial and circumferential grooves may be provided on the first seal ring 3; with reference to fig. 3, the radial groove is provided on the second sealing ring 4 and the circumferential groove is provided on the first sealing ring 3; referring to fig. 4, the radial groove is provided on the first seal ring 3 and the circumferential groove is provided on the second seal ring 4, which can be selected by those skilled in the art according to actual needs.

According to some embodiments of the present invention, referring to fig. 5 to 9, the radial groove may be configured in a plurality, and the plurality of radial grooves are arranged at intervals in a circumferential direction of the first end surface and/or the second end surface. Specifically, the plurality of radial grooves may be arranged only on the first end surface, or may be arranged only on the second end surface, and preferably, the plurality of radial grooves are arranged on both the first end surface and the second end surface.

According to some embodiments of the present invention, referring to fig. 5-9, the radial slots may further include a first radial slot 5 and a second radial slot 7, wherein the first radial slot 5 is configured in a plurality adjacent to the high pressure side H, the plurality of first radial slots 5 being circumferentially spaced apart; the second radial grooves 7 are configured in plural adjacent to the low pressure side L, the plural second radial grooves 7 are arranged at intervals in the circumferential direction, and the first radial grooves 5 are arranged alternately with the second radial grooves 7 in the circumferential direction. Specifically, a plurality of first radial grooves 5 are arranged on the high-pressure side H, a plurality of second radial grooves 7 are arranged on the low-pressure side L, the second radial grooves 7 are opposite to gaps formed by two adjacent first radial grooves 5 to form comb-tooth-shaped radial grooves, and under the combined action of pressure and temperature in the end surface gap, referring to fig. 10, the radial grooves can generate periodic deformation on the end surface, namely end surface waviness deformation.

According to some embodiments of the present invention, the radial grooves may be not communicated with the circumferential groove, or may be communicated with the circumferential groove, and referring to fig. 1 and 5, the side wall of the circumferential groove adjacent to the low pressure side L is communicated with one end of each first radial groove 5 adjacent to the high pressure side H. Specifically, a first end face of the first seal ring 3 faces a second end face of the second seal ring 4, the first seal ring 3 is a rotating ring, the second seal ring 4 is a stationary ring, the former is rotatable relative to the latter, the outer side of the end face is a high-pressure side, i.e., an upstream H, and the inner side of the end face is a low-pressure side, i.e., a downstream L. Under the action of the supply pressure, the fluid flows from the upstream H to the downstream L in the direction of the arrow G, and the pressure in the sealing gap is reduced. A first radial groove 5, a second radial groove 7 and a circumferential groove are provided at the first end face of the rotating ring. The pressure between the end faces can be maintained at a certain level from the circumferential groove to the end of the radial groove, thereby limiting the occurrence of phase change. In addition, a plane ring zone, namely a ring zone between R1 and R3, is arranged on the outer side of the circumferential groove and plays the roles of throttling and stopping sealing, and the plane ring zone can be called a sealing dam. It should be noted that R0 is the inner radius of the first end face and the second end face where the first seal ring 3 and the second seal ring 4 are just attached to each other, R1 is the outer radius of the first end face and the second end face where the first seal ring 3 and the second seal ring 4 are attached to each other, R2 is the inner radius of the circumferential groove, R3 is the outer radius of the circumferential groove, R4 is the inner radius of the first radial groove 5, R5 is the outer radius of the second radial groove 7, and Rb is the balance radius.

According to some embodiments of the invention, the circumferential groove may be continuous or discontinuous. For example, with reference to fig. 6, the circumferential groove may comprise a plurality of circumferentially spaced connecting segments, each communicating with one or more first radial grooves 5.

According to some embodiments of the present invention, with reference to fig. 5, the circumferential groove may also be configured in plurality and comprise: a first circumferential groove 6 and a second circumferential groove 8, wherein the first circumferential groove 6 is arranged adjacent to the high pressure side H and communicates with each first radial groove 5, and the second circumferential groove 8 is arranged adjacent to the low pressure side and communicates with each second radial groove 7.

According to some embodiments of the present invention, referring to fig. 5 and 6, the inner wall surfaces of the circumferential groove and the radial groove may be configured as a plane, and referring to fig. 7 and 8, the inner wall surfaces of the circumferential groove and the radial groove may be further configured as a curved surface.

According to some embodiments of the present invention, referring to fig. 3, the depth d1 of the circumferential groove may be constant or may vary. Alternatively, the circumferential groove may have the same depth in the entire circumferential direction, and at this time, the depth d1 of the circumferential groove is constant; the circumferential groove depth in the circumferential direction may also vary periodically, for example, every 60 degrees, the circumferential groove has a waviness variation, according to some embodiments of the present invention, the circumferential groove depth d1 satisfies 0.05mm ≦ d1 ≦ 2mm. Therefore, the circumferential groove adopts a deep groove, compared with a shallow groove, the deep groove has more processing modes and more available technological means, the requirement of the deep groove on the precision is relatively wide, and the production cost can be reduced to a certain extent.

According to some embodiments of the present invention, referring to fig. 4, the depth d2 of the radial groove may be constant or may vary. Alternatively, the bottom surface of the radial groove may be a flat surface, in which case the depth d2 of the radial groove is constant; the bottom surface of radial groove can also be the inclined plane, and the degree of depth of radial groove this moment is changed, according to the utility model discloses a some embodiments, the degree of depth d2 of radial groove satisfies 0.05mm and is less than or equal to d2 and is less than or equal to 2mm. Therefore, the radial groove adopts a deep groove, compared with a shallow groove, the deep groove has more processing modes and more available technological means, and the requirement of the deep groove on the precision is relatively wide, so that the production cost can be reduced to a certain extent.

According to some embodiments of the present invention, referring to fig. 5, the width D1 of the circumferential groove may be constant or may vary. Optionally, the circumferential groove is unanimous in whole ascending width in week, perhaps the bottom to the notch of circumferential groove be binding off type or uncovered type, and at this moment, the circumferential groove is radial ascending width to be changed, according to the utility model discloses a some embodiments, the width D1 of circumferential groove satisfies 0.1mm and is less than or equal to D1 and is less than or equal to 2mm.

According to some embodiments of the present invention, referring to fig. 5, the width D2 of the radial groove may be constant or may vary. Alternatively, the width of the bottom of the radial slot to the width of the slot opening may be uniform, or the bottom of the radial slot to the slot opening may be closed or open, in which case the width of the radial slot varies. According to some embodiments of the present invention, the width D2 of the radial groove satisfies 0.1mm < D1 < 2mm.

According to some embodiments of the present invention, the shape and the structure of the circumferential groove are not particularly limited, and may be a plurality of wave segments, broken line segments or curves that are continuous in the circumferential direction to adapt to different working conditions. As shown in fig. 7 and 8, the first circumferential groove may be configured in a wave shape, and the second circumferential groove may be configured in a wave shape, and according to the sizes of the first seal ring 3 and the second seal ring 4, and the kinds of different media and the distribution of the high pressure side and the low pressure side, a wave-shaped circumferential groove protruding toward the radially outer portion may be provided, and a wave-shaped circumferential groove protruding toward the radially inner portion may be provided. The circumferential groove is wavy, so that the range of fluid pressure which can be kept by the circumferential groove is larger, the circumferential groove has the effect which can be achieved by a certain radial groove, and the range of fluid pressure change which can be controlled by the circumferential groove is enlarged. In the machining process, the efficiency of machining the wavy circumferential groove is high compared with the efficiency of machining the annular circumferential groove and the radial groove simultaneously.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims (9)

1. An end face seal assembly, comprising:

a first seal ring formed with a first end face;

the second sealing ring is provided with a second end face opposite to the first end face, and a sealing gap is formed between the first end face and the second end face; wherein

At least one of the first end face and the second end face is provided with a circumferential groove, and the circumferential groove is positioned between a high-pressure side and a low-pressure side so as to control the position of fluid phase change in the sealing gap;

at least one of the first end face and the second end face is provided with a radial groove extending from a high-pressure side to a low-pressure side;

the inner wall surfaces of the circumferential groove and the radial groove are configured to be flat surfaces or curved surfaces.

2. The face seal assembly according to claim 1 wherein the radial groove is configured in plurality and the plurality of radial grooves are spaced circumferentially of the first and/or second face.

3. The face seal assembly of claim 2 wherein said radial slot comprises:

a plurality of first radial grooves configured adjacent to a high pressure side, the plurality of first radial grooves being circumferentially spaced apart;

a plurality of second radial grooves configured to be adjacent to a low pressure side, the plurality of second radial grooves being arranged at intervals in a circumferential direction, the first radial grooves being arranged to be staggered in the circumferential direction with respect to the second radial grooves.

4. The face seal assembly of claim 3 wherein the sidewall of the circumferential groove adjacent the low pressure side communicates with an end of each of the first radial grooves adjacent the high pressure side.

5. The face seal assembly of claim 3 wherein said circumferential groove includes a plurality of circumferentially spaced connecting segments, each of said connecting segments communicating with one or more first radial grooves.

6. The face seal assembly of claim 3 wherein said circumferential groove is configured in plurality and comprises:

a first circumferential groove disposed adjacent the high pressure side and in communication with each of the first radial grooves;

a second circumferential groove disposed adjacent the low pressure side and in communication with each of the second radial grooves.

7. The face seal assembly of claim 1 wherein the circumferential groove has a depth d1 and the radial groove has a depth d2 and satisfies: d1 is more than or equal to 0.05mm and less than or equal to 2mm, and d2 is more than or equal to 0.05mm and less than or equal to 2mm.

8. The face seal assembly of claim 1 wherein the circumferential groove has a width D1 and the radial groove has a width D2, and wherein: d1 is more than or equal to 0.1mm and less than or equal to 2mm, and D2 is more than or equal to 0.1mm and less than or equal to 2mm.

9. The face seal assembly according to any one of claims 1-8, wherein the circumferential groove is configured as a plurality of undulating, broken or curved segments that are circumferentially continuous.

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