CN106439037B - Sealing ring and mechanically-sealing apparatus with combination slot end face - Google Patents

Abstract

Sealing ring and mechanically-sealing apparatus with combination slot end face.Evenly arranged type groove unit is divided by the isolated part with transverse plane height on the seal face of the sealing ring, include long and short two slot in each type groove unit, two of which slot adjacent apertures are in the peripheral part of sealing ring, the slot end face that short slot and elongated slot extend on seal face is respectively at the circumference of sealing ring different radii, and the extension slot end face of short slot with the side wall of adjacent elongated slot overlap mutually；The axial depth of the slot in the leeward position in direction of rotation is more than the axial depth of the slot of position windward in two slots.Stationary ring and/or rotating ring in mechanically-sealing apparatus is using after the sealing ring with combination slot end face, the dynamic pressure effect of end face fluid film can be increased substantially, make on seal face have bigger opening force, rigidity and bearing capacity, especially with small―gap suture when effect it is more notable.

Description

Seal ring and mechanical seal device with combination groove end face

technical field

The invention relates to a seal ring with a combined groove end face in the end face fluid seal, and a mechanical seal device with the combined groove end face seal ring.

Background technique

Due to its superior performance, mechanical seal technology has been widely used in the application of numerous rotating machinery axial end face seals, such as the shaft end seals of various types of pumps, compressors, expanders, separators, reactors and other rotating machines . The basic structure of the fluid end face non-contact mechanical seal device that has been reported and/or used usually includes a stationary ring (static ring), a rotating ring (moving ring), a stationary ring seat, a shaft sleeve, a transmission pin, a tolerance Ring, compression sleeve, push ring, spring, anti-rotation pin and other components. The static ring and the moving ring are coaxially arranged opposite to each other, and their opposite end faces are sealing faces. The static ring is vacantly sleeved on the static ring seat along the radial direction, and remains relatively stationary with the stationary ring seat. The axial direction is supported by the push ring and the spring floating, and the circumferential direction is positioned by the anti-rotation pin, so that the static ring can only freely float along the axial direction. Instead of rotating with the axis. The moving ring is radially expanded by the tolerance ring on the outer cylindrical surface of the shaft sleeve, axially contacts with the step surface of the shaft sleeve and is axially compressed by the compression sleeve, and is fixed together by the transmission pin and the shaft sleeve in the circumferential direction. The moving ring can rotate synchronously with the shaft sleeve and the rotating shaft.

According to whether the sealing surface is in contact, the mechanical seal can be divided into contact type and non-contact type. Among them, the non-contact type has higher stability and longer service life. A typical method of non-contact mechanical seal is to use the flow of medium between the sealing surfaces to form a hydrodynamic pressure effect, so as to obtain sufficient fluid film opening force and high enough fluid film rigidity, so that the two sealing end faces are separated by the fluid film , to achieve non-contact operation. The hydrodynamic pressure effect of the end surface is mainly related to the surface structure of the sealing end surface, the relative speed of the sealing surface, and the viscosity of the medium. Among them, the relative speed of the sealing surface and the viscosity of the medium often depend on the site conditions of the sealing unit. More technical improvements are The surface structure of the sealing face. At present, the usual measure for setting the surface structure of the sealing end face is to set up a uniform isolation part (weir area) with the same form of end plane height on one or both end faces of the two sealing end faces of the stationary ring and the moving ring. Arranged groove forms, among which the spiral groove with equal groove depth and the end face seal of "T" groove are the most typical. How to design a better surface structure of the sealing surface and enhance the dynamic pressure effect of the end surface fluid to increase the bearing capacity and stiffness of the fluid film on the end surface, thereby improving the stability of the seal operation and ultimately prolonging the service life. It is a non-contact mechanical seal end face One of the main directions of slot type research.

Contents of the invention

The present invention firstly provides a sealing ring with a combination groove end surface for a mechanical sealing device, and a mechanical sealing device with the combination groove end surface sealing ring.

The seal ring with combined groove end face of the present invention is divided into uniformly arranged groove units on the seal end face of the seal ring by isolation parts (sealing weirs) with end plane heights, and each type groove unit includes long and short groove units. Two slots. in:

——Two grooves open adjacent to the same side of the sealing ring, and the ratio of the central angle of the center of the sealing ring corresponding to the arc length of the opening of the short groove to the central angle of the center of the sealing ring corresponding to the arc length of the opening of the long groove is 1.3~ 0.8. If the ratio is too large, the circumferential width of the long groove will be reduced, reducing the dynamic pressure effect in the long groove area; if the ratio is too small, it is not conducive to introducing more media into the sealing surface in a small gap state, and the dynamic pressure effect will not be significantly improved. ;

——The end faces of the short grooves and long grooves extending on the sealing end face are respectively located at the circumferences of different radii of the sealing ring, and the end faces of the extended grooves of the short grooves overlap with the side walls of the adjacent long grooves. For example, when the short groove of the two grooves is in the leeward position of the rotation direction, the groove end surface extending on the sealing end surface overlaps with the groove wall on the leeward side of the long groove; if the short groove of the two grooves is in the rotation direction In the windward position of the long groove, the end surface of the groove extending on the sealing end surface overlaps with the groove wall on the windward side of the long groove;

—— Among the two grooves, the axial depth of the groove at the leeward position in the direction of rotation is 2 to 30 microns, and the axial depth of the groove at the windward position is 1 to 15 microns, and the axial depth of the groove at the leeward position is greater than that at the windward position The axial depth of the groove, wherein the preferred ratio of the axial depth of the groove at the leeward position to the axial depth of the groove at the windward position is 3~1.2.

In the structure of the above-mentioned seal ring, the radial length between the outer diameter and the inner diameter of the seal ring is the radial length of the seal end face; the two long and short grooves in the groove unit opening on the periphery of the seal ring and extending on the seal end face , the radial distance from their respective peripheral notches to the respective groove end faces extending on the sealing end face is the radial length of their respective grooves. Wherein, the ratio of the radial length of the long groove to the radial length of the sealing end surface of the sealing ring is preferably 0.3-0.8. If the ratio is too small, the medium flow into the groove area will be small, which is not conducive to the formation of sufficient fluid dynamic pressure; if the ratio is too large, the radial length of the non-groove area on the sealing end surface will be small, which is not conducive to effectively preventing the leakage of the medium.

On the other hand, the ratio of the radial length of the short grooves to the radial length of the long grooves may preferably be 0.4˜0.6. If the ratio is too small, it is not conducive to the flow of the medium into the tank area to form the hydrodynamic pressure of the fraction; if the ratio is too large, the hydrodynamic pressure cannot be effectively increased, and the leakage will also increase.

On the sealing end surface, since the end surface of the extension groove of the short groove in the groove unit overlaps the side wall of the adjacent long groove, by changing or adjusting the overlapping degree, it is also possible to change and adjust the density of the medium in the sealing gap. The purpose of flow state and dynamic pressure effect. Wherein, the ratio of the central angle of the arc length of the slot extension end surface of the short slot at the overlapping portion of the adjacent side wall of the long slot to the central angle of the arc length of the opening of the short slot may preferably be 0.3-0.6. If the degree of overlap is too large, that is, the ratio is large, the reduction of the flow surface will be affected when the medium flows at the junction of the two grooves, which is not conducive to obtaining a sufficient extrusion effect, thereby affecting the dynamic pressure effect. On the contrary, It will also reduce the total amount of medium entering the long tank, and affect the dynamic pressure effect of the windward side of the long tank and the medium at the bottom of the tank.

In the above-mentioned groove unit of the sealing ring, the positions of the two long grooves and the short grooves can be set according to different specific sealing requirements. Among them, setting the long slots in the windward position and the short slots in the leeward position can be used as a commonly used preferred method.

Likewise, according to specific equipment and/or sealing requirements, the two grooves in the grooved unit may be opened on the outer peripheral portion or the inner peripheral portion of the sealing ring. Among them, the commonly used form is that both grooves are opened on the outer peripheral portion of the sealing ring, that is, the shaped groove unit is arranged in the radially outer portion of the sealing end surface. At this time, the two grooves in the groove unit are between the groove end surface extending on the sealing end surface and the inner periphery of the sealing ring, which is the sealing end surface (seal dam) with the height of the end plane; and vice versa.

The number of grooves on the sealing end surface will affect the hydrodynamic pressure effect of the sealing end surface, and with the increase of the number of grooves, the opening force, leakage and liquid film stiffness will usually increase rapidly at first, and then increase slowly and gradually become stable . Therefore, in general, on the premise of meeting the requirements of various aspects, increasing the number of the above-mentioned groove units in the sealing end face is conducive to improving the sealing performance. However, in consideration of factors such as meeting needs and processing costs, the number of groove units provided on the sealing end surface is generally at least 6, and the preferred number is 6-30.

As far as the long and short grooves in the type groove unit are concerned, there is no special requirement, and conventional grooves that have been reported and/or used so far can be used. Due to the different groove types set on the sealing end face, the impact on the fluid dynamic pressure effect, opening force, leakage, liquid film stiffness and other factors in the sealed state, as well as the applicable equipment and/or working conditions, etc. different. Although the long and short grooves in the groove unit can be selected separately according to needs without any special limitations or requirements, it can be understood that the greater the difference between the two groove types, the greater the impact on the sealing effect. The influencing factors will also be more complex or controlled. Therefore, in general, the long and short grooves in the same type of groove unit are preferably the same type of groove, such as spiral grooves, straight grooves, arc grooves, etc., even if it is to adapt to or meet specific equipment and /or different types of grooves are used for combination due to the needs of working conditions, and the combination of grooves with similar groove types is also preferred (such as spiral grooves and arc grooves, etc.).

In the specific design, according to the actual requirements for sealing, one of the two grooves in the groove unit can be determined in a conventional way, and then according to the conventional method of the other groove and the above-mentioned relative parameter relationship between the two grooves, the obtained Another slot. Taking two grooves as spiral grooves as an example, according to the conventional formula ① of the edge profile of the spiral groove, the long groove (or short groove) in the groove unit can be designed first, and then according to the formula and the above-mentioned The relevant parameter relationship range of , you can get the short slot (or long slot) adjacent to it:

①.

r _in formula ① is the polar radius of the logarithmic helix in polar coordinates ( r _i ≤ r ≤ r ₀ ), ri is the base circle of the logarithmic helix, which is the radius of the inner circle of the sealing ring, and φ is the logarithmic helix The polar angle at the start (0~180°), θ is the logarithmic helix polar angle (can be determined as required), and β is the helix angle (can be determined as required).

On the basis of the combination groove sealing ring mentioned above, the present invention further provides a mechanical seal device with a combination groove sealing ring. The rotating ring has a sealing end face between its opposite end faces, and the stationary ring is mutually positioned by the anti-rotation pin and the static ring seat in the circumferential direction, and is floatingly supported in the stationary ring seat by an axially arranged spring and a push ring; the rotating ring can pass through the shaft The sleeve is connected with the shaft as a transmission. Wherein, at least one of the stationary ring and the rotating ring is the combination groove end face sealing ring with the groove unit on the sealing end face.

Calculations show that the adoption of the above-mentioned mechanical seal device with a combination groove seal ring of the present invention can significantly improve the dynamic pressure effect of the fluid film on the sealing end face, so that the sealing end face has greater opening force, stiffness and bearing capacity, especially in the small gap state (gap less than 3 microns), it obviously has better fluid film characteristics than the traditional sealing end face, effectively increasing the hydrodynamic pressure effect of the end face.

The sealing ring with the above-mentioned structure of the present invention and the mechanical sealing device using the sealing ring have wide applicability. For example, it can be set to a variety of seal layouts according to needs, including single-end seals, double-end seals, series seals (more than two stages), series with a middle labyrinth (more than two stages), etc., and can also be combined with floating ring seals, Carbon ring seals, labyrinth seals and other seal types are combined into a combined seal structure application.

The above content of the present invention will be further described in detail below in conjunction with the specific implementation manners of the embodiments shown in the accompanying drawings. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following examples. Without departing from the above-mentioned technical idea of the present invention, various replacements or changes made according to common technical knowledge and customary means in this field shall be included in the scope of the present invention.

Description of drawings

Fig. 1 is a schematic structural view of a mechanical seal device using the present invention with a combination groove end face seal ring.

Fig. 2 is a schematic diagram of an arrangement state of groove units of the sealing ring in Fig. 1 on the sealing end surface.

Fig. 3 is an enlarged structural schematic diagram of a groove unit area in the sealing end face of Fig. 2 .

Detailed ways

What Fig. 1 shows is to adopt a kind of mechanical sealing device of the present invention with combined groove end face sealing ring. The structure is the same as the current conventional mechanical seal device, which has a stationary ring 5 and a rotating ring 7 arranged coaxially opposite each other, and there is a sealing end face with _a gap h0 between the opposite end faces. h ₀ can generally be 0~0.025 mm, and can be adjusted according to the actual situation. For example, for ordinary mechanical seals, the two sealing end faces are basically in direct contact without gaps; for gas non-contact sealing end faces, the gap h ₀ of the groove-free area is usually about 0.002~0.005 mm; for some liquid film non-contact mechanical seals _{The gap h0} of the sealed end face without groove is generally about 0.01~0.025 mm. The stationary ring 5 is mutually positioned by the anti-rotation pin 14 and the stationary ring seat 8 in the circumferential direction, and is floatingly supported in the stationary ring seat 8 by the axially arranged spring 13 and the push ring 12; And shaft 11 is connected for transmission. Among them, the stationary ring 5 and/or the rotating ring 7 is a combined groove end surface with 6 to 30 (for example, 12) groove units 6 composed of long grooves 2 and short grooves 1 evenly arranged on the outer peripheral side of the sealing end surface sealing ring.

Fig. 2 and Fig. 3 are a kind of structural forms of the end face sealing ring with combination groove in Fig. 1 . The inner radius r4 of the sealing ring is 60mm, and the outer radius r1 is 81mm. On the sealing end surface of the sealing ring, the isolation part (sealing weir) 3 with the height of the end plane is divided into evenly arranged groove units 6 of the same structure, and each groove unit 6 includes long grooves of spiral groove type. 2 and the short slot 1, and the short slot 1 is in the leeward position in the direction of rotation, and the long slot 2 is in the windward position. The two grooves are adjacent to the outer peripheral edge of the seal ring, and _the central angle θ ₁ of the center of the seal ring corresponding to the opening arc length AB of the short groove 1 and the central angle θ 2 of the seal ring center corresponding to the opening arc length BC of the long groove 2 The ratio is θ ₁ : θ ₂ =1. The end faces of the short groove 1 and the long groove 2 extending on the sealing end face are respectively located at the circumferences of the seal rings with different radii r2 (r2=76mm) and r3 (r3=71mm), and the end face of the extension groove of the short groove 1 is adjacent to The side walls 15 of the elongated groove 2 overlap each other. The ratio of the central angle θ 3 of the arc length DE of the groove extension end surface arc length DE of the short groove ₁ to the overlapping portion of the side wall 15 adjacent to the long groove 2 and the central angle θ ₁ of the opening arc length AB of the short groove 1 is θ ₃ : θ ₁ =0.4. The two grooves extend on the sealing end surface and between the end surface of the groove and the inner peripheral edge of the sealing ring is a sealing end surface (seal dam) 4 with the height of the end plane.

The radial distance between the two grooves from their peripheral openings to the groove end faces extending on the sealing end face is respectively the radial length of the grooves. The ratio of the radial length of the short groove 1 to the radial length of the long groove 2 ranges from 0.5, and the ratio of the radial length of the long groove 2 to the radial length of the sealing end surface is 0.48.

Among the two grooves, the axial depth h _{g 1} of the short groove 1 at the leeward position is 10 microns, and the axial depth h _{g 2} of the groove 2 is 5 microns.

In the specific design, according to the actual requirements of the sealing parameters/conditions, the long groove 2 (or short groove 1) of the two grooves can be designed according to the above-mentioned formula ① of the edge profile of the spiral groove, and then according to the formula ① and the gap between the two grooves According to the above parameter relationship requirements, the corresponding short slot 1 (or long slot 2) can be obtained. The relevant parameters in formula ① are the same as above, where the polar radius is r _i ≤ r≤r ₀ , the polar angle φ at the beginning of the logarithmic helix is 0~180°, and the polar angle θ of the logarithmic helix can be determined according to specific requirements , The helix angle β is 5°～30°.

Comparing calculation results with ordinary spiral grooves of the same type of size and parameters, when the gap between the sealing surfaces is 1 micron, the opening force of the medium between the sealing surfaces of this example with combined groove end face seal rings can be increased by about 90% compared with ordinary spiral grooves. %, the fluid film stiffness increases by about 900%; when the sealing surface gap is 2 microns, the medium opening force of the sealing surface of the combination groove of the present invention can be increased by about 60% compared with the ordinary spiral groove, and the fluid film stiffness is increased by about 650%. It has been shown that the sealing ring with the combined groove end face of the present invention can effectively increase the dynamic pressure effect of the end face fluid, especially when small gaps are sealed, the sealing ring with the combined groove end face of the present invention can improve the rigidity of the fluid film and the opening force. Greater advantage.

Claims (12)

1. The sealing ring with combined groove end surface is characterized in that the sealing end surface of the sealing ring is divided into evenly arranged groove units (6) by the isolation part (3) with the height of the end plane, and each type groove unit (6) ) includes two long and short slots (2, 1), where: ——Two grooves open adjacent to the same side of the sealing ring, where the central angle ( θ ₁ ) of the center of the sealing ring corresponding to the opening arc length (AB) of the short groove (1) is the same as the opening arc length of the long groove (2) (BC) The ratio of the central angle ( θ ₂ ) corresponding to the center of the sealing ring is 1.3~0.8; ——The end faces of the short groove (1) and the long groove (2) extending on the sealing end face are respectively at the circumferences of different radii (r2, r3) of the sealing ring, and the end face of the extending groove of the short groove (1) is in the same position as the adjacent The side walls (15) of the long slots (2) overlap each other; - of the two grooves, the axial depth ( h _{g 1} ) of the groove in the leeward position in the direction of rotation is 2 to 30 μm, and the axial depth ( h _{g 2} ) of the groove in the windward position is 1 to 15 μm, and The axial depth ( h _{g 1} ) of the groove at the leeward position is greater than that at the windward position ( h _{g 2} ). 2. The sealing ring according to claim 1, characterized in that the radial distance between the two grooves from their peripheral openings to the non-groove end faces extending on the sealing end face is the radial length of the groove, wherein the short groove ( The ratio of the radial length of 1) to the radial length of the long groove (2) is 0.4-0.6. 3. The seal ring according to claim 1, characterized in that the central angle ( θ ₃ ), and the ratio of the central angle ( θ ₁ ) of the opening arc length (AB) of the short groove (1) is 0.3~0.6. 4. The sealing ring according to claim 1, characterized in that the ratio of the axial depth ( h _{g 1} ) of the groove at the leeward position to the axial depth ( h _{g 2} ) of the groove at the windward position is 3-1.2. 5. The sealing ring according to claim 2, characterized in that the ratio of the radial length of the long groove (2) to the radial length of the sealing end face of the sealing ring is 0.3-0.8. 6. The sealing ring according to claim 1, characterized in that the long groove (2) is a groove in a windward position, and the short groove (1) is a groove in a leeward position. 7. The sealing ring according to claim 1, characterized in that the groove unit (6) is arranged in the radially outer part of the sealing end surface, and the two grooves in the groove unit (6) are on the sealing end surface Between the end surface of the extended groove and the inner peripheral edge of the sealing ring is a sealing end surface with the height of the end plane. 8. The sealing ring according to any one of claims 1 to 7, characterized in that the two grooves in the groove unit (6) are of the same type. 9. The sealing ring according to claim 8, characterized in that the two grooves in the groove unit (6) are both spiral grooves. 10. The sealing ring according to claim 8, characterized in that the number of said groove units (6) provided on the sealing end face is at least six. 11. The sealing ring according to claim 10, characterized in that the number of the groove units (6) provided on the sealing end surface is 6-30. 12. A mechanical seal device with combined groove sealing rings, with a stationary ring (5) and a rotating ring (7) arranged coaxially opposite each other, the opposite end faces are sealing end faces, and the stationary ring (5) is surrounded by anti-rotation pins (14) is mutually positioned with the static ring seat (8), and is floatingly supported in the static ring seat (8) by the axially arranged spring (13) and push ring (12); the rotating ring (7) is passed through the shaft sleeve (9) ) is connected with the shaft (11), characterized in that the stationary ring (5) and/or the rotating ring (7) is provided with a groove unit as described in one of claims 1 to 11 on the sealing end face ( 6) The combination groove end face seal ring.