CN107366748B - A VW mechanical seal end face structure - Google Patents

Abstract

The VW type mechanical seal end face structure comprises a mechanical seal moving ring and a static ring, wherein one side of the moving ring and the static ring is a high-pressure side, namely an upstream side, the other side of the moving ring and the static ring is a low-pressure side, namely a downstream side, a smooth planar annular seal dam is arranged at the downstream side of the end face, a plurality of periodically distributed dynamic pressure type grooves are formed in the high-pressure side of the seal end face, each dynamic pressure type groove consists of a V-shaped groove and a W-shaped groove, grooves at two sides of the V-shaped groove and the W-shaped groove extend radially, the width of the grooves at the upstream side, namely the high-pressure side and the low-pressure side of the end face is gradually narrowed, and the depth of the grooves is gradually shallower; the W-shaped groove is radially extended, the widths of the upstream high-pressure side and the downstream low-pressure side of the end face are equal, the depths are equal, and a non-slotting area between the V-shaped groove and the W-shaped groove is a sealing weir. The invention provides a VW mechanical seal end face structure which has good backflow effect, strong fluid dynamic pressure effect, wear resistance and excellent leakage control and fluid film bearing capacity.

Description

A VW mechanical seal end face structure

technical field

The invention belongs to the technical field of end face mechanical seal structure design, in particular to a deep end face seal structure composed of a V-shaped groove and a W-shaped groove, belongs to the technical field of fluid sealing, and is suitable for transposition of shaft end seals of various types of compressors, industrial pumps, kettles and other rotating machines.

Background technique

Mechanical seals are indispensable components in various fluid machinery, power machinery and other rotating machinery. Among them, the non-contact mechanical seal is widely used in various high-parameter rotary fluid machines due to its advantages of low wear, low energy consumption, high pressure resistance and small leakage. There are many types of sealing end faces that can rotate in both directions, such as T-shaped grooves, king-shaped grooves, double-helical grooves, etc. These fluid-type grooves have low friction power consumption and good stability, but their performance in the bearing capacity of the fluid film and control of the leakage rate is average, and the start-up performance is not ideal. By developing and optimizing the fluid-type groove structure of the sealing end face. This kind of sealed two-way rotary pump has obvious return flow effect, good dynamic pressure effect, large bearing capacity, high wear resistance and can reduce leakage at the same time.

Contents of the invention

In order to overcome the disadvantages of the existing two-way rotating mechanical seal groove, such as insignificant backflow effect, insufficient leakage prevention and insufficient bearing capacity, the present invention provides a VW type mechanical seal end face structure with good backflow effect, strong fluid dynamic pressure effect, wear resistance, and excellent performance in leakage control and fluid film bearing capacity.

The technical scheme adopted in the present invention is:

A VW-type mechanical seal end face structure, including a dynamic ring and a static ring of a mechanical seal. One side of the dynamic ring and the static ring is the high pressure side, that is, the upstream, and the other side of the dynamic ring and the static ring is the low pressure side, that is, the downstream. The downstream of the end face is provided with a smooth and flat annular seal dam. The high pressure side of the seal end face is provided with a plurality of periodically distributed dynamic pressure grooves. The dynamic pressure grooves are composed of V-shaped grooves and W-shaped grooves. narrower and shallower in depth; the inner groove of the W-shaped groove extends radially and has the same width and depth from the upstream high-pressure side to the downstream low-pressure side of the end face, and the ungrooved area between the V-shaped groove and the W-shaped groove is a sealing weir.

Further, the dynamic pressure grooves are evenly distributed in the circumferential direction, and the number thereof is 8-12.

Still further, the included angle α ₁ of the inner wall of the V-shaped groove in the dynamic pressure groove is 40°-60°, and the included angle α ₂ of the outer wall is 80°-85°. The lengths on both sides of the V-shaped groove are different, and the upstream and downstream widths and depths of the grooves change linearly.

Furthermore, the two side walls of the W-shaped groove of the dynamic pressure groove are parallel to the two side walls of the V-shaped groove, and the distance between the two parallel walls is 1-3mm. The lengths of both sides of the outer groove of the W-shaped groove are different, and the upstream and downstream width and depth of the groove change linearly, the upstream depth is 40-50 μm, and the downstream depth is 5-10 μm. The upstream width is 500-700 μm, and the downstream width is 100-200 μm.

Preferably, the depth and width of the upper and lower sides of the inner side of the W-shaped groove of the dynamic pressure type groove are equal, and the depth is 5-10 μm; the included angle β of the inner side groove is 40°-60°.

Preferably, the distance between the downstream end of the V-shaped groove and the upstream end of the inner groove of the W-shaped groove is 50-100 μm. The W-shaped groove starts on the upstream side and ends at the sealing dam.

The V-shaped groove and the W-shaped groove of the present invention can be converging grooves that gradually converge or converge in steps along the radial direction.

The working principle of the present invention: when the end face of the VW mechanical seal is started, one side of the V-shaped groove and one side of the W-shaped groove on the end face can quickly absorb the sealing medium in the sealing chamber, and gather it downstream of the groove to form a high-pressure area. The sealing medium continuously drawn from the V-shaped groove flows back into the sealing chamber along the other side of the groove, while the sealing medium of the W-shaped groove forms multiple high-pressure areas in the radial direction under the action of the sealing weir, which enhances the dynamic pressure effect of the fluid film, reduces wear under frequent start-stop conditions, and finally flows back into the sealing chamber. Leakage is reduced. The W-shaped groove can also store a certain sealing medium, which can ensure a certain fluid film stiffness, and the blocking effect of the sealing dam can reduce leakage during the operation of the mechanical seal.

The beneficial effects of the present invention are as follows: 1. Strong backflow can be formed under the synergistic effect of the two types of grooves, and zero leakage can be realized under low pressure conditions. 2. The hydrodynamic pressure effect generated by multiple converging grooves is strong, and the opening characteristics are good to extend the service life of the seal. The sealing medium stored in the W-shaped groove area can improve the rigidity of the fluid film and ensure the stability of the sealing operation. 3. When the seal is transposed without rotation requirements, it can be rotated in one direction or two directions, which can effectively control the leakage rate.

Description of drawings

Fig. 1 is a schematic view of the end face structure of the present invention.

Fig. 2 is a schematic diagram of a VW-type stepped converging groove.

Fig. 3 is a schematic diagram of the structure of the double V-groove end face.

Fig. 4 is a schematic diagram of double V-shaped grooves with stepped convergent grooves.

specific implementation plan

Further illustrate the present invention below in conjunction with accompanying drawing.

Example 1

Referring to Fig. 1 and Fig. 2, a VW type mechanical seal end face structure includes a dynamic ring and a static ring of a mechanical seal. One side of the dynamic ring and the static ring is the high pressure side, namely the upstream side, and the other side of the dynamic ring and the static ring is the low pressure side, the downstream side. A smooth and flat annular seal dam 3 is provided downstream of the end face, and a plurality of periodically distributed dynamic pressure grooves 5 are provided on the high pressure side of the seal end face. The dynamic pressure grooves are composed of V-shaped grooves 1 and W-shaped grooves 2. From the upstream, that is, from the high-pressure side to the downstream low-pressure side, the width gradually narrows and the depth gradually becomes shallower; the inner groove of the W-shaped groove extends radially, and the width and depth from the upstream high-pressure side to the downstream low-pressure side of the end face are equal. The ungrooved area between the V-shaped groove and the W-shaped groove is the sealing weir 4 .

Further, the dynamic pressure grooves 5 are uniformly distributed in the circumferential direction, and the number thereof is 8-12.

Further _, the included angle α 1 of the inner wall of the V-shaped groove 1 in the dynamic pressure groove 5 is 40°-60°, and the included angle α ₂ of the outer wall is 80°-85°. The lengths on both sides of the V-shaped groove 1 are different, and the upstream and downstream widths and depths of the grooves change linearly.

Further, the two side walls of the W-shaped groove of the dynamic pressure groove 5 are parallel to the two side walls of the V-shaped groove, and the distance between the two parallel walls is 1-3mm. The lengths of both sides of the outer groove of the W-shaped groove are different, and the upstream and downstream width and depth of the groove change linearly, the upstream depth is 40-50 μm, and the downstream depth is 5-10 μm. The upstream width is 500-700 μm, and the downstream width is 100-200 μm.

The depth and width of the upper and lower sides of the W-shaped groove 2 of the dynamic pressure groove are equal, and the depth is 5-10 μm; the angle β of the inner groove wall is 40°-60°.

The distance between the downstream end of the V-shaped groove 1 and the upstream end of the inner groove of the W-shaped groove 2 of the dynamic pressure groove 5 is 50-100 μm. The W-shaped groove 2 starts from the upstream side and ends at the sealing dam 3 .

Example 2

Referring to Fig. 3 and Fig. 4, the difference between this embodiment and embodiment 1 is that the dynamic pressure groove is composed of double V-shaped grooves, both of which present a convergent structure with a deep upstream and a shallow downstream. For the specific depth size range, refer to embodiment 1. The angle range of the inner and outer walls of the small V-shaped groove 62 can refer to embodiment 1, the inner wall of the large V-shaped groove is parallel to the outer wall of the small V-shaped groove, and the angle α ₃ of the outer wall of the large V-shaped groove 61 is 90 ° ~ 95 °. This groove type can generate high-pressure areas in the downstream area of the two V-shaped grooves, and the positions are different, so it can enhance the dynamic pressure effect on the overall end surface, improve the rigidity of the fluid liquid film, and improve the start-up characteristics of the seal.

The content described in the embodiments of this specification is only an enumeration of the implementation forms of the inventive concept, and the protection scope of the present invention should not be regarded as limited to the specific forms stated in the embodiments, and the protection scope of the present invention also covers equivalent technical means that those skilled in the art can think of according to the inventive concept.

Claims (6)

1. The utility model provides a VW type mechanical seal terminal surface structure, includes mechanical seal's moving ring and quiet ring, one side of moving ring and quiet ring be the high pressure side and be the upper reaches, the opposite side of moving ring and quiet ring is the low pressure side and be the low reaches, terminal surface structure low reaches are equipped with smooth planar annular seal dam, its characterized in that: the high pressure side of the end face structure is provided with a plurality of periodically distributed dynamic pressure type grooves, each dynamic pressure type groove consists of a V-shaped groove and a W-shaped groove, two side grooves of each V-shaped groove and two outer side grooves of each W-shaped groove extend radially, the width of each V-shaped groove is gradually narrowed from the upstream side of the end face structure, namely the high pressure side to the downstream low pressure side, and the depth of each V-shaped groove is gradually shallower; the inner side groove of the W-shaped groove extends radially, and the widths and the depths of the inner side groove are equal from the upstream high pressure side to the downstream low pressure side of the end face structure; the two side grooves of the V-shaped groove are positioned between the two outer side grooves of the W-shaped groove and at the upstream of the two inner side grooves of the W-shaped groove, the two side walls of the outer side groove of the W-shaped groove of the dynamic pressure type groove are respectively parallel to the two side walls of the V-shaped groove, the distance between the two parallel wall surfaces is 1-3 mm, the distance between the downstream end of the V-shaped groove of the dynamic pressure type groove and the upstream end of the inner side groove of the W-shaped groove is 50-100 mu m, and the ungrooved area between the V-shaped groove and the W-shaped groove is a sealing weir.

2. The VW mechanical seal end face structure of claim 1, wherein: the dynamic pressure type grooves are uniformly distributed in the circumferential direction, and the number of the dynamic pressure type grooves is 8-12.

3. The VW-type mechanical seal end face structure of claim 1 or 2, characterized in that: the included angle of the inner side wall of the V-shaped groove in the dynamic pressure type grooveα ₁ The included angle of the outer side wall is 40-60 degreesα ₂ The width and depth of the upstream and downstream of the grooves at the two sides of the V-shaped groove are linearly changed, the depth of the upstream is 30-40 mu m, and the depth of the downstream is 5-15 mu m; the upstream width is 500-700 μm, and the downstream width is 200-300 μm.

4. The VW-type mechanical seal end face structure of claim 1 or 2, characterized in that: the upstream width, the downstream width and the depth of the two outer side grooves of the W-shaped groove are linearly changed, the upstream depth is 40-50 mu m, the downstream depth is 5-10 mu m, the upstream width is 500-700 mu m, and the downstream width is 100-200 mu m.

5. The VW-type mechanical seal end face structure of claim 1 or 2, characterized in that: the depth and width of the upstream and downstream of the W-shaped groove inner side groove of the dynamic pressure type groove are equal, and the depth is 5-10 mu m; the included angle of the wall of the inner side grooveβIs 40-60 degrees.

6. The VW-type mechanical seal end face structure of claim 1 or 2, characterized in that: the W-groove originates at the upstream side and ends at the annular sealing dam.