Double-rotation-direction dynamic pressure enhancing sealing ring

Abstract

The present invention provides a double-rotation-direction dynamic-pressure enhanced sealing ring, comprising: a double-rotation-direction sealing dynamic ring. A plurality of T-shaped grooves are evenly distributed along the circumferential direction on the groove surface end of the double-rotation-direction sealing dynamic ring. A pair of pressurizing holes are provided on the groove bottom surface of the arc groove inside the double-rotation-direction sealing dynamic ring. The pressurizing holes are stepped holes axially penetrating through the double-rotation-direction sealing dynamic ring. A one-way duckbill valve is installed in the large-diameter hole of each pressurizing hole. Through CFD simulation, the end-face gas film pressure distribution and opening force of the novel sealing dynamic ring structure of the present invention and the original structure are calculated and compared. The results show that the end-face opening force of the novel double-rotation-direction dynamic-pressure enhanced sealing ring of the present invention is increased by 2% - 4.6% compared with the original design. Especially when the rotational speed is lower than 5000 revolutions per minute, the dynamic-pressure enhancement effect is more obvious. The double-rotation-direction dry gas seal with this structural design will have excellent low-speed opening performance. It can effectively solve the problem of dry friction on the end face of the dry gas seal under the conditions of lower sealing gas pressure and lower rotational speed.

Description

Technical Field

[0001] The present invention belongs to the technical field of dry gas seals, and in particular, to a double-rotation-direction hydrodynamic-enhanced seal ring. Background Art

[0002] Dry gas seals are usually used to solve the shaft-end sealing problems of high-speed rotating machinery such as centrifugal compressors. It belongs to non-contact gas-lubricated mechanical seals, and generally consists of a shaft sleeve, a dynamic ring, a static ring, a spring, auxiliary sealing rings and other structural components. The biggest difference between it and ordinary mechanical seals is that several-micron-deep hydrodynamic grooves are machined on the end face of the dynamic ring. When the dynamic and static rings rotate relative to each other, the end-face microgrooves shear the gas, forming a local high pressure at the root of the grooves, so that a gas film with a very high stiffness is formed between the entire dynamic and static rings, and the entire friction pair shows a tendency to separate outward. The medium pressure acts on the back of the dynamic and static rings, and together with the spring force, forms a total closing force, which also makes the friction pair show a tendency to close. The closing force and the opening force of the dry gas seal are equal during stable operation.

[0003] The design of the hydrodynamic grooves of dry gas seals is one of the most important links in the entire seal design work, directly related to the success or failure of the seal application. Through long-term research, it has been found that the logarithmic spiral or Archimedes spiral hydrodynamic groove type has the best hydrodynamic effect. Dry gas seal manufacturers represented by John Crane mainly adopt single-rotation-direction spiral groove shapes. It has the advantages of large gas film stiffness and strong anti-interference ability. However, due to the geometric feature limitations of the single-rotation-direction hydrodynamic grooves, there are fatal disadvantages in specific application environments. For example, when the compressor rotates in the reverse direction, the seal end face with a single-rotation-direction groove type cannot generate an opening force, and contacts and rubs for a relatively long time, and the seal end face is extremely easy to be damaged.

[0004] In addition, dry gas seals are located at both ends of the compressor cylinder block. Taking the normal direction of the main shaft passing through the cylinder block as the positive direction, the rotation directions of the seals at both ends are just opposite. If single-rotation-direction dry gas seals are used, two sets of products with two rotation directions need to be equipped for the dry gas seal products of the same batch, one set for operation and one set for standby. Taking a single-cylinder compressor as an example, it must be equipped with two sets of dry gas seals with clockwise and counterclockwise rotation directions respectively. If double-rotation-direction dry gas seals that are not affected by the rotation direction are used, the seals at the driving end and the non-driving end of the compressor can be interchanged, and the number of spare parts is reduced. Therefore, double-rotation-direction dry gas seals have a broad industrial application field and are irreplaceable. It is of great significance to conduct in-depth research on the hydrodynamic groove type of double-rotation-direction dry gas seals.

[0005] The double-rotation-direction hydrodynamic pressure grooves have a common feature: If the groove platform area is equally divided circumferentially according to the number of grooves, within a certain periodic division area, the groove shapes will be symmetrically distributed along the central radial straight line. When the seal operates normally, half of the grooves generate positive pressure to open the end face, and the other half generate negative pressure to make the end face tend to fit. Through CFD calculation, it is found that the hydrodynamic pressure opening force of the end face is almost 0 at this time. Summary of the Invention

[0006] In view of the problems of the above-mentioned prior art, the object of the present invention is to solve the problems and provide a double-rotation-direction dynamic pressure enhancing sealing ring.

[0007] To achieve the above-mentioned invention object, the technical solution of the present invention is as follows:

[0008] A double-rotation-direction dynamic pressure enhancing sealing ring, comprising: a double-rotation-direction sealing dynamic ring 1, a plurality of T-shaped grooves 2 are evenly distributed circumferentially on the groove surface end 5 of the double-rotation-direction sealing dynamic ring 1. The T-shaped grooves 2 do not penetrate the double-rotation-direction sealing dynamic ring 1 axially. Each T-shaped groove 2 includes a straight groove 21 extending from the outer diameter to the inner diameter of the groove surface end 5 and an arc groove 22 connected to the end of the straight groove 21. The width of the arc groove 22 is greater than the width of the straight groove 21. The side of the double-rotation-direction sealing dynamic ring 1 without T-shaped grooves is the back end 6. A pair of pressurizing holes 3 are provided on the groove bottom surface of the arc groove 22 located inside the double-rotation-direction sealing dynamic ring 1. The pressurizing holes 3 are stepped holes axially penetrating the double-rotation-direction sealing dynamic ring 1, including a small-diameter hole 31 near the groove surface end 5 and a large-diameter hole 32 near the back end 6. A one-way duckbill valve 4 is installed in the large-diameter hole 32 of each pressurizing hole 3, and the duckbill end 42 of the duckbill valve 4 extends into the small-diameter hole 31.

[0009] As a preferred mode, each pair of pressurizing holes 3 is symmetrically arranged about the center line of the arc groove on the groove bottom surface of the arc groove 22 where it is located.

[0010] As a preferred mode, 6-20 T-shaped grooves are evenly distributed circumferentially on the groove surface end 5 of the double-rotation-direction sealing dynamic ring 1.

[0011] As a preferred mode, 3-6 T-shaped grooves equally spaced in the circumferential direction of the double-rotation-direction sealing dynamic ring 1 are selected to set the pressurizing holes 3. The reason for such setting is that it can make the pressure distribution of the pressurizing holes on the entire sealing dynamic ring 1 more balanced and uniform, and make the total dynamic pressure formed by the entire groove group positive.

[0012] As a preferred mode, when the number of T-shaped grooves is odd, the number of pairs of pressurizing holes 3 is an odd number of 3 or more; when the number of T-shaped grooves is even, the number of pairs of pressurizing holes 3 is an even number of 4 or more.

[0013] As a preferred mode, the depth of the T-shaped grooves in the groove surface end 5 of the double-rotation-direction sealing dynamic ring 1 is 8-10 micrometers.

[0014] As a preferred embodiment, the one-way duckbill valve is used to control the on-off of the air flow at the groove surface end and the back end of the double-rotation sealing dynamic ring 1. When the pressure at the back end of the double-rotation sealing dynamic ring is higher than that at the groove surface end and greater than the opening pressure of the duckbill valve, the medium gas flows from the back end of the double-rotation sealing dynamic ring to the groove surface end of the dynamic ring; when the pressure at the groove surface end of the double-rotation sealing dynamic ring is higher than that at the back end and greater than the closing pressure of the duckbill valve, the duckbill valve closes and the air flow is cut off.

[0015] As a preferred embodiment, the one-way duckbill valve 4 includes a rubber seat 41 and a duckbill part 42, and the duckbill part 42 is fixed on the rubber seat 41.

[0016] As a preferred embodiment, the double-rotation sealing dynamic ring 1 is made of SiC material.

[0017] As a preferred embodiment, the aperture of the small-diameter hole 31 of the pressure-increasing hole 3 is 0.2 - 0.6 mm, and the aperture of the large-diameter hole is 3 - 6 mm.

[0018] The beneficial effects of the present invention are as follows: The present invention proposes a new double-rotation dynamic pressure enhancing sealing ring. Through CFD simulation, the end face air film pressure distribution and opening force of the new sealing dynamic ring structure of the present invention are calculated and compared with those of the original structure. The results show that the end face opening force of the new double-rotation dynamic pressure enhancing sealing ring of the present invention is increased by 2% - 4.6% compared with the original design. Especially when the rotational speed is lower than 5000 revolutions per minute, the dynamic pressure enhancing effect is more obvious, and the double-rotation dry gas seal with this structural design will have excellent low-speed opening performance. It can effectively solve the problem of dry friction at the end face of the dry gas seal under the conditions of lower sealing gas pressure and lower rotational speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the overall structural schematic diagram of the double-rotation dynamic pressure enhancing sealing ring of the present invention;

[0020] Figure 2 is Figure 1 the sectional view taken along line E-E in

[0021] Figure 3 is Figure 2 the partial enlarged view of

[0022] Figure 4 is the three-dimensional installation schematic diagram of the one-way duckbill valve of the present invention in the double-rotation dynamic pressure enhancing sealing ring.

[0023] Figure 5 is the structural schematic diagram of the one-way duckbill valve of the present invention.

[0024] 1 is the double-rotation sealing dynamic ring, 2 is the T-shaped groove, 21 is the straight groove, 22 is the arc groove, 3 is the pressure-increasing hole, 31 is the small-diameter hole, 32 is the large-diameter hole, 4 is the one-way duckbill valve, 41 is the rubber seat, 42 is the duckbill end, 5 is the groove surface end, and 6 is the back end. Detailed implementation mode

[0025] The following uses specific specific examples to illustrate the implementation mode of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0026] This embodiment provides a double-rotation-direction dynamic pressure boosting sealing ring, including: a double-rotation-direction sealing dynamic ring 1. A plurality of T-shaped grooves 2 are evenly distributed along the circumferential direction on the groove surface end 5 of the double-rotation-direction sealing dynamic ring 1. The T-shaped grooves 2 do not penetrate the double-rotation-direction sealing dynamic ring 1 axially. Each T-shaped groove 2 includes a straight groove 21 extending from the outer diameter to the inner diameter of the groove surface end 5 and an arc groove 22 connected to the end of the straight groove 21. The width of the arc groove 22 is greater than the width of the straight groove 21. The side of the double-rotation-direction sealing dynamic ring 1 without T-shaped grooves is the back end 6. A pair of boosting holes 3 are provided on the groove bottom surface of the arc groove 22 inside the double-rotation-direction sealing dynamic ring 1. The boosting holes 3 are stepped holes that penetrate the double-rotation-direction sealing dynamic ring 1 axially, including a small-diameter hole 31 near the groove surface end 5 and a large-diameter hole 32 near the back end 6. A one-way duckbill valve 4 is installed in the large-diameter hole 32 of each boosting hole 3, and the duckbill end 42 of the duckbill valve 4 extends into the small-diameter hole 31.

[0027] Each pair of boosting holes 3 is symmetrically arranged about the center line of the arc groove on the groove bottom surface of the arc groove 22 where it is located.

[0028] 6 - 20 T-shaped grooves are evenly distributed along the circumferential direction on the groove surface end 5 of the double-rotation-direction sealing dynamic ring 1.

[0029] Select 3 - 6 T-shaped grooves that are equally spaced in the circumferential direction of the double-rotation-direction sealing dynamic ring 1 to set the boosting holes 3. The reason for this setting is that it can make the pressure distribution of the boosting holes on the entire sealing dynamic ring 1 more balanced and uniform, and make the total dynamic pressure formed by the entire groove group positive.

[0030] When the number of T-shaped grooves is odd, the number of pairs of boosting holes 3 is an odd number greater than or equal to 3; when the number of T-shaped grooves is even, the number of pairs of boosting holes 3 is an even number greater than or equal to 4.

[0031] The depth of the T-shaped grooves in the groove surface end 5 of the double-rotation-direction sealing dynamic ring 1 is 8 - 10 micrometers.

[0032] The one-way duckbill valve is used to control the on-off of the air flow at the groove surface end and the back end of the double-rotation sealing dynamic ring 1. When the pressure at the back end of the double-rotation sealing dynamic ring is higher than that at the groove surface end and greater than the opening pressure of the duckbill valve, the medium gas flows from the back end of the double-rotation sealing dynamic ring to the groove surface end of the dynamic ring; when the pressure at the groove surface end of the double-rotation sealing dynamic ring is higher than that at the back end and greater than the closing pressure of the duckbill valve, the duckbill valve closes and the air flow is cut off.

[0033] The one-way duckbill valve 4 includes a rubber seat 41 and a duckbill part 42, and the duckbill part 42 is fixed on the rubber seat 41.

[0034] The double-rotation sealing dynamic ring 1 is made of SiC material.

[0035] The aperture of the small-diameter hole 31 of the pressure-increasing hole 3 is 0.2 - 0.6 mm, and the aperture of the large-diameter hole is 3 - 6 mm.

[0036] This embodiment proposes a new double-rotation dynamic pressure boosting sealing ring. Through CFD simulation, the end face gas film pressure distribution and opening force of the new sealing dynamic ring structure and the original structure are calculated and compared. The results show that the end face opening force of the new double-rotation dynamic pressure boosting sealing ring of the present invention is increased by 2% - 4.6% compared with the original design. Especially when the rotational speed is lower than 5000 r / min, the dynamic pressure boosting effect is more obvious. The double-rotation dry gas seal with this structural design will have excellent low-speed opening performance. It can effectively solve the problem of dry friction at the end face of the dry gas seal under the conditions of lower sealing gas pressure and lower rotational speed.

[0037] It is particularly worth pointing out that this design is not only useful for the T-shaped groove, but also applicable to other double-rotation groove types.

[0038] The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A double-rotation-direction dynamic pressure boosting sealing ring, characterized in that, Comprising: A double-rotation-direction sealing dynamic ring (1), on the groove surface end (5) of the double-rotation-direction sealing dynamic ring (1), a plurality of T-shaped grooves (2) are evenly distributed circumferentially. The T-shaped grooves (2) do not penetrate the double-rotation-direction sealing dynamic ring (1) axially. Each T-shaped groove (2) includes a straight groove (21) extending from the outer diameter to the inner diameter of the groove surface end (5) and an arc groove (22) connected to the end of the straight groove (21). The width of the arc groove (22) is greater than the width of the straight groove (21). The side of the double-rotation-direction sealing dynamic ring (1) without T-shaped grooves is the back end (6). On the bottom surface of the arc groove (22) inside the double-rotation-direction sealing dynamic ring (1), a pair of pressure-increasing holes (3) are provided. The pressure-increasing holes (3) are stepped holes axially penetrating the double-rotation-direction sealing dynamic ring (1), including a small-diameter hole (31) close to the groove surface end (5) and a large-diameter hole (32) close to the back end (6). A one-way duckbill valve (4) is installed in the large-diameter hole (32) of each pressure-increasing hole (3), and the duckbill end (42) of the one-way duckbill valve (4) extends into the small-diameter hole (31).

2. The double-rotation-direction dynamic pressure boosting seal ring according to claim 1, wherein: Each pair of pressure-increasing holes (3) is symmetrically arranged about the center line of the arc groove on the bottom surface of the arc groove (22) where it is located.

3. The double-rotation-direction hydrodynamic efficiency-enhancing sealing ring according to claim 1, characterized in that: 6 - 20 T-shaped grooves are evenly distributed circumferentially on the groove surface end (5) of the double-rotation-direction sealing dynamic ring (1).

4. The double-rotation-direction hydrodynamic efficiency-enhancing sealing ring according to claim 1, wherein: Pressure-increasing holes (3) are provided on 3 - 6 T-shaped grooves evenly distributed circumferentially on the double-rotation-direction sealing dynamic ring (1).

5. The dual-rotation dynamic pressure enhancement sealing ring according to claim 3 or 4, characterized in that: When the number of T-shaped grooves is odd, the number of pairs of pressure-increasing holes (3) is an odd number greater than 3; when the number of T-shaped grooves is even, the number of pairs of pressure-increasing holes (3) is an even number greater than 4.

6. The double-rotation-direction dynamic pressure boosting sealing ring according to claim 1, wherein: The depth of the T-shaped grooves in the groove surface end (5) of the double-rotation-direction sealing dynamic ring (1) is 8 - 10 microns.

7. The double-rotation-direction hydrodynamic efficiency-enhancing sealing ring according to claim 1, wherein: The one-way duckbill valve is used to control the on-off of the gas flow between the groove surface end and the back end of the double-rotation-direction sealing dynamic ring (1). When the pressure at the back end of the double-rotation-direction sealing dynamic ring is higher than the pressure at the groove surface end and greater than the opening pressure of the one-way duckbill valve, the medium gas flows from the back end of the double-rotation-direction sealing dynamic ring to the groove surface end of the dynamic ring; when the pressure at the groove surface end of the double-rotation-direction sealing dynamic ring is higher than the pressure at the back end and greater than the closing pressure of the one-way duckbill valve, the one-way duckbill valve closes and the air flow is cut off.

8. The double-rotation-direction dynamic pressure boosting sealing ring according to claim 1, wherein: The one-way duckbill valve (4) includes a rubber seat (41) and a duckbill end (42), and the duckbill end (42) is fixed on the rubber seat (41).

9. The double-rotation-direction dynamic pressure boosting sealing ring according to claim 1, characterized in that: The double-rotation-direction sealing dynamic ring (1) is made of SiC material.

10. The double-rotation-direction dynamic pressure boosting seal ring according to claim 1, characterized in that: The aperture of the small-diameter hole (31) of the pressure-increasing hole (3) is 0.2 - 0.6 mm, and the aperture of the large-diameter hole is 3 - 6 mm.

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