CN202188125U - Spherical mechanical sealing device - Google Patents

Abstract

The utility model relates to a spherical mechanical seal device, characterized by: the mechanical seal static ring (1) is provided with a spherical surface a, the rotating ring (2) is provided with a spherical surface b, and the spherical surface a and the spherical surface b are matched to form a sealing surface which can be directly contacted with each other or separated with a small gap. The advantages are that: compared with the traditional mechanical seal, the spherical mechanical seal device has better deformation resistance, in particular to the capabilities of resisting the torsional deformation of a shaft section and the bending deformation of a main shaft of a unit. The utility model is suitable for a shaft end seal of various rotary machines.

Description

Spherical mechanical seal

technical field

The utility model belongs to the shaft end seal of a rotating machine, in particular to a spherical mechanical sealing device, which can be used for shafts of various types of rotating machines such as compressors, expanders, separators, pumps, and reactors. end seal.

Background technique

Mechanical seals are widely used on shaft ends of many rotating machines. Due to the complexity of their working conditions, in-depth research on mechanical seals will be a long-term, arduous and must be continuously advanced process, especially the shape and performance of the sealing mating surface. Research has always been the focus and difficulty of sealing technology research. The research and development of the shaft end dynamic seal of rotating machinery has mainly gone through two processes:

1. Radial seal

Early rotary machinery spindle seals used labyrinth seals. Labyrinth seals had a large amount of leakage and could only be used in low-pressure situations. Complex auxiliary systems were usually required to deal with a large amount of seal leakage gas. The second generation of rotating machinery spindle seals are floating ring seals with oil film lubrication. In a typical floating ring seal, there are two sets of sealing surfaces, and oil with a pressure slightly higher than the pressure of the sealed medium is injected into the sealing system to prevent the leakage of the sealed medium and cool the sealing element at the same time. To this day, a small number of floating ring seals still operate on rotating machines. Floating ring seals have disadvantages such as large consumption of blocking fluid, complex oil sealing system, large investment, large floor space, and high operation and maintenance costs.

Both the labyrinth seal and the floating ring seal are radial seals, which seal the radial space between the main shaft and the stationary sealing surface. Because it is necessary to ensure sufficient clearance to prevent contact between the main shaft and the stationary sealing surface, the technical level and service life that this type of seal can achieve are limited.

2. End seal

In 1950, researchers developed a contact mechanical seal and applied it in the refrigeration industry to prevent expensive coolant from leaking along the axial direction. The contact mechanical seal belongs to the end face seal, which is different from the radial seal. The actual sealing surface is the two surfaces (planes) perpendicular to the main shaft of the rotating machine. This structure allows the dynamic and static seals to contact directly during the workpiece process, thereby greatly Significantly improve the sealing performance.

The early mechanical seals were contact mechanical seals, mainly wet seals. Later, on the basis of contact mechanical seals, technicians researched and developed non-contact mechanical seals, especially dry-running gas end face seals (dry gas Seal) has achieved very successful application in the shaft end seal of rotating machinery represented by compressors.

The current mechanical seal belongs to the end face seal, and its actual sealing surface is the two surfaces (planes) perpendicular to the main shaft of the rotating machine. Its characteristics are:

1) Insensitive to the wear of the sealing surface. After the surface of the contact seal is worn, the floating ring will automatically compensate the amount of wear under the action of the closing force, while the non-contact seal basically has no surface wear.

2) It has good followability to axial movement.

The above two points are summed up, in fact, they all show the superior performance of the end face seal against movement, wear and other factors along the direction of the rotation axis, but when the torsional deformation of the seal end face along the shaft section occurs, or the main shaft of the unit where the moving ring is located bends and deforms, The degree of contact between the two sealing end faces will become stronger or weaker locally, resulting in an increase in the local contact pressure between the two sealing surfaces and increased friction and wear. For non-contact seals, it may cause the circumferential pulsation of the fluid film pressure on the end faces, and the sealing surface will locally Direct contact may occur, seriously affecting seal life. For the above problems, the spherical mechanical seal has stronger adaptability.

In summary, a spherical mechanical seal device is designed, which has better resistance to torsional deformation of the shaft section and bending deformation of the main shaft of the unit, thereby further broadening the scope of application of the mechanical seal and improving the use of the unit seal. life.

Contents of the invention

The purpose of the utility model is to provide a spherical mechanical sealing device, which has better ability to resist torsional deformation of the shaft section and bending deformation of the main shaft of the unit.

The purpose of this utility model is achieved in this way: a spherical mechanical seal device is composed of a stationary ring 1 with a spherical surface a, a rotating ring 2 with a spherical surface b and other related parts, the spherical surface a on the stationary ring 1 is in contact with the rotating The spherical surfaces b on the ring 2 are installed face-to-face to form a sealing surface. The sealing surface may be that the spherical surfaces a and b are in direct contact, or that the spherical surfaces a and b are separated by a small gap. The characteristic is that the sealing surface is spherical.

The utility model mainly adopts the following technical measures to realize:

The spherical surface a and the spherical surface b of the spherical mechanical sealing device can be convex or concave, but when the spherical surface a is convex (concave), the spherical surface b must be concave (convex).

The radius of the convex surface of the spherical mechanical sealing device is smaller than or equal to the radius of the concave surface.

The radii of the spherical surface a and the spherical surface b of the spherical mechanical sealing device may be equal or unequal.

In the spherical surface a and the spherical surface b of the spherical mechanical sealing device, a fluid dynamic pressure groove can be provided on one or both spherical surfaces at the same time, or neither of the spherical surfaces can be provided with a fluid dynamic pressure groove.

In the spherical mechanical seal device, the fluid dynamic pressure groove provided on the spherical surface can be a deep groove or a shallow groove, and the groove depth ranges from 0.01 micron to 3 mm.

The sealing arrangement of the spherical mechanical seal device may be a single-stage seal with only one set of sealing surfaces, or a series seal or double-end seal composed of more than two sets of sealing surfaces.

The spherical mechanical seal device may be a combined seal formed by a spherical mechanical seal and other forms of dynamic seals in a multi-stage seal arrangement.

The utility model has the following characteristics:

1) The sealing end face is spherical;

2) It has better ability to resist the torsional deformation of the shaft section and the bending deformation of the main shaft of the unit.

Description of drawings

Fig. 1 is a schematic diagram of a contact seal structure in which two sealing surfaces are in direct contact in the spherical mechanical seal device of the present invention.

Fig. 2 is a schematic diagram of the structure of the spherical sealing surface on the static ring in the spherical contact mechanical seal device of the present invention.

Fig. 3 is a schematic diagram of the structure of the spherical sealing surface on the moving ring in the spherical contact mechanical seal device of the present invention.

Fig. 4 is a schematic diagram of a non-contact sealing structure in which two sealing surfaces are separated by a small gap in the spherical mechanical sealing device of the present invention.

Fig. 5 is a schematic diagram of a non-contact sealing structure in which evenly distributed shallow hydrodynamic pressure grooves are engraved on the sealing surface of the moving ring in the spherical mechanical sealing device of the present invention.

Fig. 6 is a schematic diagram of the structure of the shallow groove on the end surface of the dynamic spherical sealing surface in the spherical non-contact mechanical sealing device of the present invention.

The symbols in the drawings have the following meanings:

SR ₁ ——Spherical radius of convex sealing surface.

SR ₂ ——Spherical radius of concave sealing surface.

R ₃ ——shaft sleeve outer diameter.

R ₄ ——Inner diameter of the shallow groove on the sealing surface.

R ₅ ——The outer diameter of the shallow groove on the sealing surface.

a——Spherical surface on the stationary ring.

b—the spherical surface on the rotating ring.

c—Shallow groove structure on the sealing surface.

ω ₁ ——The rotational angular velocity of the rotating ring.

h ₀ ——Axial clearance of the end face of the non-contact spherical mechanical seal.

H—upstream (high pressure side).

L - downstream (low pressure side).

Detailed ways

The utility model is analyzed below in conjunction with embodiment.

There are many kinds of specific implementations of the utility model, which are analyzed and explained according to different examples of the contact mode of the spherical mechanical seal and whether a dynamic pressure groove is provided on the sealing surface.

Embodiment 1: Refer to Fig. 1, Fig. 2, Fig. 3

Fig. 1 is a schematic structural view of Embodiment 1 of the present utility model. The spherical mechanical seal device includes a stationary ring 1 with a spherical surface a, a rotating ring 2 with a spherical surface b, a stationary ring seat 3, a shaft sleeve 4, an "O" ring 5, a tolerance ring 6, a compression sleeve 7, a push Ring 8, spring 9, anti-rotation pin 10, etc. The feature of this embodiment is that the two sealing surfaces (namely: spherical surface a and spherical surface b) are in direct contact.

According to Figure 1, Figure 2 and Figure 3, the spherical surface a on the stationary ring 1 is a concave surface with a radius of SR ₁ , the spherical surface b on the rotating ring 2 is a convex surface with a radius of SR ₂ , and the relationship between the radii of the two spherical surfaces is: SR _{1 ≥SR2} . The stationary ring 1 and the rotating ring 2 are installed face-to-face on the same axis to form a spherical sealing surface. The sealing surface is in direct contact with spherical surface a and spherical surface b, which is a contact mechanical seal device.

The outer diameter side of the seal ring is the upstream side H, the inner diameter side is the downstream side L, the flow direction of the medium leakage is from the outer diameter side (upstream side) to the inner diameter side (downstream side), and the function of the spherical sealing surface is to prevent the medium leakage flow.

Embodiment 2: Refer to Fig. 4

Fig. 4 is a schematic structural view of Embodiment 2 of the present utility model. The spherical mechanical seal device includes a stationary ring 1 with a spherical surface a, a rotating ring 2 with a spherical surface b, a stationary ring seat 3, a shaft sleeve 4, an "O" ring 5, a tolerance ring 6, a compression sleeve 7, a push Ring 8, spring 9, anti-rotation pin 10, etc. The feature of this embodiment is that the two sealing surfaces (namely: spherical surface a and spherical surface b) are separated by a small gap h0.

According to Figure 4, the spherical surface a on the stationary ring 1 is a concave surface with a radius of SR ₁ , the spherical surface b on the rotating ring 2 is a convex surface with a radius of SR ₂ , and the stationary ring 1 and the rotating ring 2 are installed face-to-face on the same axis. And separated by a small gap h ₀ to form a spherical non-contact sealing surface, which is a non-contact mechanical seal device.

The outer diameter side of the seal ring is the upstream side H, the inner diameter side is the downstream side L, the flow direction of the medium leakage is from the outer diameter side (upstream side) to the inner diameter side (downstream side), and the role of the spherical non-contact sealing surface It is to prevent the leakage flow of the medium.

Embodiment 3: refer to Fig. 5, Fig. 6

Fig. 5 and Fig. 6 are structural schematic diagrams of Embodiment 3 of the present utility model. The spherical mechanical seal device includes a stationary ring 1 with a spherical surface a, a rotating ring 2 with a spherical surface b, a stationary ring seat 3, a shaft sleeve 4, an "O" ring 5, a tolerance ring 6, a compression sleeve 7, a push Ring 8, spring 9, anti-rotation pin 10, etc. The characteristic of this embodiment is that a fluid dynamic pressure groove c is provided on the dynamic ring-shaped sealing surface b.

According to Fig. 5, the spherical surface a on the stationary ring 1 is a concave surface with a radius of SR ₁ , and the spherical surface b on the rotating ring 2 is a convex surface with a radius of SR ₂ , and the relationship between the radii of the two spherical surfaces is: SR ₁ >SR ₂ . The stationary ring 1 and the rotating ring 2 are installed face-to-face on the same axis, and the two sealing surfaces are separated by a small gap _h0 under the fluid dynamic pressure of the shallow groove c to form a spherical non-contact sealing surface, which belongs to the non-contact mechanical seal device.

The outer diameter side of the seal ring is the upstream side H, the inner diameter side is the downstream side L, the flow direction of the medium leakage is from the outer diameter side (upstream side) to the inner diameter side (downstream side), and the role of the spherical non-contact sealing surface It is to prevent the leakage flow of the medium.

In the above embodiments, the focus is on the contact mode of the spherical mechanical seal and whether a dynamic pressure groove is provided on the sealing surface. In order to describe the core problem more clearly, the above embodiments only involve a single-stage sealing structure, but in actual use, the overall layout of the seal can have various types according to needs, such as: single-end seal, double-end seal, tandem seal (above two stages), series with intermediate labyrinth (above two stages), can also be combined with floating ring seal, carbon ring seal, labyrinth seal and other sealing types to form a combined seal.

Claims (7)

1. sphere mechanical seal device; Form by the stationary ring that has sphere a (1), the rotating ring (2) and other correlated parts that have a sphere b; Sphere b on sphere a on the stationary ring (1) and the rotating ring (2) is face-to-face installation, forms sealing surface, and the sealing face can be that sphere a directly contacts with sphere b; Also can be that sphere a separates with a micro-gap with sphere b, it is characterized in that: sealing surface be spherical shape.

2. sphere mechanical seal device according to claim 1 is characterized in that: sphere a and sphere b both can be that convex surface also can be a concave surface, but when sphere a was convex surface, sphere b was necessary for concave surface, and when sphere a was concave surface, sphere b was necessary for convex surface.

3. sphere mechanical seal device according to claim 1 and 2 is characterized in that: recessed sealing surface spherical radius SR1 can equate with protruding sealing surface spherical radius SR2, also can be unequal.

4. sphere mechanical seal device according to claim 1 is characterized in that: among sphere a and the sphere b, can or on two spheres, fluid dynamic pressure groove be set simultaneously at one, or two spheres are not provided with fluid dynamic pressure groove.

5. sphere mechanical seal device according to claim 4 is characterized in that: the fluid dynamic pressure groove that is provided with on the sphere can be that deep trouth also can be a shallow slot, and its groove depth scope is between 0.01 micron～3 millimeters.

6. sphere mechanical seal device according to claim 1 is characterized in that: the layout of sealing can be to have only the single-stage sealing of one group of sealing surface, tandem seal or the double seals that also can be made up of sealing surface more than two groups.

7. sphere mechanical seal device according to claim 6 is characterized in that: during two groups of above sealing surfaces are arranged, can be the sphere mechanical seal combination seal that sealing forms with conventional machinery.

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