CN101806362A - Mechanical sealing device of middle rotating ring - Google Patents

Abstract

The invention relates to an intermediate rotating ring mechanical seal device, which is characterized in that: an intermediate rotating ring (2) is added between the mechanical seal stationary ring (1) and the rotating ring (4), and the rotating speed of the intermediate rotating ring (2) can be adjusted The rotation speed of the rotating shaft of the unit to be sealed can be higher or lower through the regulation of the middle rotating ring driving member (3). Both sides of the middle rotating ring (2) are sealing end faces. Its advantage is: compared with the traditional mechanical seal, the speed of the rotating shaft of the sealed unit no longer determines the relative rotational speed between the end faces of the mechanical seal, which can make the low (high) speed unit have a higher (lower) relative rotation between the sealing end faces. Speed, so that the units with different speeds can maintain a reasonable end face relative rotation speed. The invention is applicable to the shaft end sealing devices of various rotating machines, especially the sealing devices of low-speed and high-speed units.

Description

Intermediate rotary ring mechanical seal

technical field

The invention belongs to the shaft end seal of a rotary machine, in particular to an intermediate rotary ring mechanical seal device, which can be used in various types of compressors, expanders, separators, pumps, reactors, etc. Machine shaft end seal.

Background technique

Mechanical seals are widely used in many rotating machinery shaft ends. Due to the complexity of the working conditions, the in-depth research on mechanical seals will be a long-term, arduous and must be continuously promoted process, especially the shaft end seals of high-speed and low-speed units. Stability has always been two difficult issues that plague researchers. The specific manifestations are: the relative speed between the sealing surfaces of the contact mechanical seal is too high at high speed, resulting in serious friction, wear, heat, deformation and other phenomena of the sealing surface, the sealing performance drops rapidly, and even cannot work normally; the non-contact mechanical seal Under the condition of low speed, the fluid film between the end faces cannot generate enough opening force and rigidity, and the normal separation of the sealing surface and the stability of the gap cannot be guaranteed. Therefore, it is necessary to study a mechanical seal technology with adjustable relative speed of the sealing surface. On the one hand, the relative speed of the high-speed contact mechanical seal end face is reduced, and on the other hand, the relative speed of the low-speed non-contact mechanical seal end face is increased. Mechanical seals can work in a reasonable speed range, thereby increasing the stability of the seal and prolonging its service life.

For high-speed contact mechanical seals, in order to reduce serious phenomena such as friction, wear, heat, and deformation of the sealing surface, the following countermeasures are mainly adopted:

(1) Research on friction pair materials

Commonly used friction pair hard annulus materials include: cemented carbide, ceramics, special steel, and cast metal. Among them, cemented carbide and ceramic materials are used more, and silicon carbide and silicon nitride are used in practice. , Mostly tungsten carbide. In particular, in recent years, there have been research reports on the application of diamond materials in sealing, and a few companies have planned to develop ultra-nanocrystalline diamond technology to seal the end face. Commonly used soft ring surfaces for friction pairs include: carbon graphite, copper alloy, and resin. Among them, carbon graphite has become the most commonly used soft ring surface with the highest usage rate due to its good self-lubricating properties, corrosion resistance, easy processing and good heat transfer. Torus material.

(2) Research on the heat dissipation of the sealing body, especially the dynamic and static rings

The main measures are to choose materials with good heat dissipation, improve the flushing conditions of the seal, and optimize the design of the seal structure. Due to the limitation of the flow rate (flushing amount) of the seal-related medium, the heat in most seals cannot be taken away by greatly increasing the fluid flow rate, and the friction pair is difficult to find both the dynamic and the static due to the constraints of other conditions such as corrosion resistance and low friction. The heat dissipation of the ring is very good material pairing. Therefore, research in this direction can only improve the stability of the seal to a certain extent, and it is difficult to get rid of the fundamental influence of high speed.

The research on friction pair materials is limited by material technology, and it is not yet possible to fundamentally improve the stability of the seal under high-speed conditions, but its effect is constantly advancing with the deepening of research.

For non-contact mechanical seals, equal-groove deep spiral grooves and "T" groove end face seals are the most typical. How to enhance the hydrodynamic pressure effect of the end face to increase the bearing capacity and stiffness of the fluid film on the end face, thereby improving the stability of the seal operation, prolonging the service life, and expanding the application of the seal is a main direction for the research and future development of non-contact mechanical seals. The relative rotation speed between the paired sealing end faces is a key factor affecting the fluid film load capacity and fluid film stiffness of the end faces, and the fluid film load capacity and fluid film stiffness of the end faces are basically linearly proportional to the relative rotation speed between the end faces. For a long time, due to the influence of the fixed thinking and the limitation of unit conditions, there have been no research reports and practical products to find a suitable relative rotation speed of the sealing end surface without the speed of the unit to be sealed, which makes some shafts with higher and lower speeds The end seal stability and life are significantly reduced, especially for low speed units. The current research is still mainly focused on the optimization of the seal face groove and its parameters.

Chinese patent 02146449.9 discloses a double helix angle three-dimensional helical groove end face sealing device, as shown in FIG. 1 . Its characteristics are: the upstream of the spiral groove is wider, that is, the high pressure side, and the downstream, that is, the low pressure side, is narrower, and the depth of the spiral groove gradually becomes shallower from the upstream, that is, the high pressure side, to the downstream, that is, the low pressure side, thus forming a three-dimensional convergent spiral groove. The double-helix-angle three-dimensional helical groove end face sealing device can obtain greater fluid film rigidity, but it is very difficult to process the inclined groove bottom.

Chinese patent 02132978.8 discloses a mechanical seal with a spiral groove end face composed of a family of angular microgrooves, as shown in FIG. 2 . The direction of the angular microgrooves is consistent with the direction of the spiral grooves, and the structure of the shallow grooves on the sealing end surface is relatively complicated. Because the angular microgrooves are distributed along the direction of the spiral grooves and there is no obvious contraction shape, it is difficult to greatly improve the stiffness of the fluid film on the end surface.

According to the current sealing end surface groove type, the spiral groove is a groove type structure with the largest fluid film carrying capacity and fluid film rigidity, but for units with low speed, because of the too low relative rotation speed of the end surface, it has already affected its The bottleneck of the strength of the hydrodynamic pressure effect on the end surface, the optimization of the groove shape of the end surface has been difficult to fundamentally improve the formation of hydrodynamic pressure.

To sum up the above reasons, an intermediate rotating ring mechanical seal device is designed. The intermediate rotating ring mechanical seal device can make the sealing end faces of different speed units obtain a suitable relative rotation speed, so as to get rid of the speed of the sealed unit on the sealing performance. The impact of the impact, improve the service life of the higher (low) speed unit seal.

Contents of the invention

The object of the present invention is to provide a mechanical seal device for an intermediate rotating ring, which can be adapted to a unit with a wider rotation speed range, especially a unit with a high (low) rotation speed.

The object of the present invention is achieved in this way: a kind of intermediate rotating ring mechanical seal device, by the stationary ring 1 with sealing end face, the intermediate rotating ring 2 with sealing end face, the rotating ring 4 with sealing end face and other related parts Composition, the stationary ring 1 and the intermediate rotating ring 2, and the sealing end surfaces of the intermediate rotating ring 2 and the rotating ring 4 are installed face to face, and the sealing surfaces can be directly bonded or separated by a small gap. It is characterized in that an intermediate rotating ring 2 with adjustable speed is placed between the stationary ring 1 and the rotating ring 4 .

The present invention mainly adopts following technical measure to realize:

The relative rotational speed of the sealing surface of the intermediate rotating ring mechanical seal device can be adjusted, and the rotational speed of the unit to be sealed does not directly determine the rotational speed of the sealing end surface.

The control of the relative rotational speed of the sealing surface of the intermediate rotating ring mechanical seal device is realized by adjusting the rotating speed of the intermediate rotating ring 2 .

The arrangement of the intermediate rotating ring mechanical seal device can be a single-stage seal with only one intermediate rotating ring 2, or a series seal or double-end seal composed of more than two intermediate rotating rings 2 and their matching ring bodies.

The intermediate rotating ring mechanical seal device can be of contact type or non-contact type.

A fluid dynamic pressure groove can be provided on the end face of the intermediate rotating ring mechanical seal device as required.

The present invention has the following characteristics:

1. The relative speed of the sealing end face can be adjusted;

2. The speed of the sealed unit does not directly determine the relative speed of the sealing end face;

3. Make the high-speed contact mechanical seal and low-speed non-contact mechanical seal have higher stability.

Description of drawings

Fig. 1 is a schematic diagram of the end surface structure of a three-dimensional helical groove with a double helix angle disclosed in Chinese patent 02146449.9.

Fig. 2 is a schematic diagram of the end surface structure of a spiral groove composed of angular microgrooves disclosed in Chinese patent 02132978.8.

Fig. 3 is a schematic diagram of the structure of the intermediate rotating ring in the present invention in which the driving mode is contact and the driving position is located outside the outer diameter of the ring.

Fig. 4 is a schematic diagram of the structure of the intermediate rotating ring in the present invention, in which the driving mode is contact, and the driving position is located on the inner diameter side of the ring.

Fig. 5 is a structural schematic diagram of the present invention in which the drive mode of the intermediate rotating ring is non-contact.

Fig. 6 is a schematic structural view of the shallow grooves on the end faces of the present invention located on both end faces of the middle rotating ring.

Fig. 7 is a schematic diagram of a structure where shallow grooves on the end face of the present invention are located.

Fig. 8 is a structural schematic view of shallow grooves on the end face of the present invention located on the middle rotating ring and the ring surface paired with one end face of the middle rotating ring.

The symbols in the drawings have the following meanings:

R ₁ ——Inner radius of hydrodynamic pressure groove on end face.

R ₂ ——The outer radius of the hydrodynamic pressure groove on the end face.

h ₁ ——The depth of the high-pressure side of the hydrodynamic pressure groove on the end face.

h ₂ ——The depth of the low-pressure side of the hydrodynamic pressure groove on the end face.

S _a1 ——The profile line of the main groove wall of the hydrodynamic pressure groove on the end face.

S _a2 ——The profile line of the auxiliary groove wall of the hydrodynamic pressure groove on the end face.

a——There is a groove area on the end face.

b - sealing weir.

c——seal dam.

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

H—upstream (high pressure side).

L - downstream (low pressure side).

Detailed ways

The present invention is analyzed below in conjunction with embodiment.

There are many kinds of specific implementations of the present invention. Here, examples are analyzed and explained based on differences in the driving mode, driving position, and position of the end surface of the intermediate ring.

Embodiment 1: Refer to Fig. 3

Fig. 3 is a schematic structural diagram of Embodiment 1 of the present invention. The intermediate rotating ring mechanical seal device includes a stationary ring 1, an intermediate rotating ring 2, an intermediate rotating ring driver 3, a rotating ring 4, an "O" ring 5, a shaft sleeve 6, a tolerance ring 7, a compression sleeve 8, and a push ring 9. Spring 10, anti-rotation pin 11, static ring seat 12, etc. The feature of this embodiment is that the intermediate rotating ring is in direct contact with the driving member 3 and is driven, and the driving position is on the outer diameter side of the sealing end face.

According to Fig. 3, the intermediate rotating ring is connected with the power source, and directly drives the intermediate rotating ring on the outer diameter side, and the speed of the intermediate rotating ring is affected by the rotating speed of the power source of the driving member 3 and its intermediate speed change mechanism. The stationary ring 1, the intermediate rotating ring 2 and the rotating ring 4 are installed face-to-face and coaxially. The rotating ring is fixed together with the sealed shaft in the circumferential direction through the shaft sleeve 6, the tolerance ring 7, and the compression sleeve 8, and the "O" ring 5 is used to prevent leakage between the contact surfaces, and the stationary ring is passed through the push ring 9 and the spring 10 , anti-rotation pin 11, fixed together with the stationary ring seat 12 in the circumferential direction, the middle rotating ring is axially placed between the rotating ring and the stationary ring, a group of sealing end faces F ₁ are formed between the stationary ring and the middle rotating ring, and the middle rotating ring Another set of sealing end faces F ₂ are formed between it and the rotating ring. The main shaft speed of the unit to be sealed is equal to the speed of the rotating ring at ω ₁ and the speed of the middle rotating ring at ω ₂ .

The relative rotational speed between two sealing faces can be calculated as follows:

ω _F1 ＝ω ₂ (1) formula

ω _F2 ＝|ω ₁ ±ω ₂ | (2) formula

ω _F1 and ω _F2 represent the relative rotational speed between the sealing end faces F ₁ and F ₂ respectively.

For low speed units:

Assumption: ω ₁ =50(rpm)

Because the rotational speed of the intermediate rotating ring 2 is variable, it can be adjusted as: ω ₂ =10000 (rpm)

but:

From formula (1): ω _F1 = 10000 (rpm)

From formula (2): ω _F2 = 10050 (rpm), or ω _F2 = 9950 (rpm)

It can be seen that for a unit whose rotational speed of the sealed shaft is only 50 (rpm), by using and properly adjusting the rotational speed of the intermediate rotating ring 2, both the sealing end faces F ₁ and F ₂ can obtain a sufficiently high relative rotational speed.

For high speed units:

Assumption: ω ₁ =16000(rpm)

Because the rotational speed of the intermediate rotating ring 2 is variable, it can be adjusted as: ω ₂ =8000 (rpm)

but:

From formula (1): ω _F1 = 8000 (rpm)

From formula (2): ω _F2 = 8000 (rpm) (take ω ₁ and ω ₂ in the same direction)

It can be seen that for a unit with a rotational speed of the sealed shaft of 15000 (rpm), by using and properly adjusting the rotational speed of the intermediate rotating ring 2, the relative rotational speed of the sealing end faces F ₁ and F ₂ can be significantly reduced. If the number of intermediate rotating rings 2 is increased, the relative rotational speed of the sealing end face will further decrease.

In the above calculation, the specific value of the rotational speed has no specific meaning, it is only to illustrate the change of the relative rotational speed between the sealing end faces F ₁ and F ₂ after adding the intermediate rotating ring.

Embodiment 2: Refer to Fig. 4

Fig. 4 is a schematic structural diagram of Embodiment 2 of the present invention. Its sealing structure and key technical requirements are basically the same as those of Embodiment 1. The main difference is that in Embodiment 2, the driving position of the intermediate rotating ring 2 is set on the inner diameter side, and the calculation and calculation of the relative rotational speed between the sealing end faces F ₁ and F ₂ Change situation is identical with embodiment 1.

Embodiment 3: Refer to Fig. 5

Fig. 5 is a schematic structural diagram of Embodiment 3 of the present invention. Its key feature is that the intermediate rotating ring 2 is not in direct contact with the driving member 3 of the intermediate rotating ring, and the driving of the intermediate rotating ring 2 is realized in a non-contact manner. The calculation and change of the relative rotational speed between the sealing end faces F ₁ and F ₂ are the same as those in Embodiment 1.

Embodiment 4: Refer to Fig. 6

Fig. 6 is a schematic structural diagram of Embodiment 4 of the present invention. Its key feature is that hydrodynamic pressure grooves are arranged on the end faces of both sides of the middle rotating ring 2 . The calculation and change of the relative rotational speed between the sealing end faces F ₁ and F ₂ are the same as those in Embodiment 1.

Embodiment 5: Refer to Fig. 7

Fig. 7 is a schematic structural diagram of Embodiment 5 of the present invention. Its key feature is: a fluid dynamic pressure groove is set on the sealing surface matched with the end surfaces on both sides of the middle rotating ring 2 . The calculation and change of the relative rotational speed between the sealing end faces F ₁ and F ₂ are the same as those in Embodiment 1.

Embodiment 6: Refer to Fig. 8

Fig. 8 is a schematic structural diagram of Embodiment 6 of the present invention. Its key features are: one set of hydrodynamic pressure grooves on the sealing end face is set on the middle rotating ring 2 , and the other set of hydrodynamic pressure grooves on the sealing end face is set on the sealing surface matched with the middle rotating ring 2 . The calculation and change of the relative rotational speed between the sealing end faces F ₁ and F ₂ are the same as those in Embodiment 1.

In the above analysis, the focus is on reflecting the driving mode and driving position of the intermediate rotating ring 2, and the influence on the relative speed of the sealing surface. This is because the purpose of adding the intermediate rotating ring 2 is to adjust the relative rotating speed of the sealing end face to a reasonable range. It breaks the traditional situation that the speed of the sealed shaft is the relative speed of 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 (15)

1. rotating ring mechanical seal device in the middle of a kind, form by the stationary ring that has seal face (1), the middle rotating ring (2) that has seal face, middle rotating ring actuator (3), the rotating ring (4) and other correlated parts that have a seal face, stationary ring (1) is face-to-face installation with middle rotating ring (2), middle rotating ring (2) with the seal face of rotating ring (4), can directly fit between the seal face, also can separate in a very little gap.It is characterized in that: the middle rotating ring (2) that between stationary ring (1) and rotating ring (4), is placed with the rotating speed adjustable control.

2. rotating ring mechanical seal device in the middle of according to claim 1 is characterized in that: the rotating speed size of middle rotating ring (2) is more than or equal to zero, turns to rotating ring to turn in the same way or oppositely.

3. according to claim 1,2 described in the middle of the rotating ring mechanical seal device, it is characterized in that: the number of middle rotating ring (2) is for more than or equal to arbitrary integer of 1.

4. according to claim 1,2,3 described in the middle of the rotating ring mechanical seal device, it is characterized in that: the power source of middle rotating ring (2) can be sealed unit, also can be other additionaling power source.

5. according to claim 1,2,3,4 described in the middle of the rotating ring mechanical seal device, it is characterized in that: the driving mode of middle rotating ring (2) can be a contact-type, also can be contactless.

6. according to claim 1,2,3,4,5 described in the middle of the rotating ring mechanical seal device, it is characterized in that: the activation point of middle rotating ring (2) can be on inside and outside anchor ring, or any one position of middle rotating ring ring body.

7. according to claim 1,2,3,4,5,6 described middle rotating ring mechanical seal device, it is characterized in that: form one group of seal face between stationary ring (1) and the middle rotating ring (2), form another group seal face between middle rotating ring (2) and the rotating ring (4).

8. according to claim 1,7 described middle rotating ring mechanical seal device is characterized in that: in every group of seal face, can or on two end faces fluid dynamic pressure groove be set simultaneously at one, or two end faces are not provided with fluid dynamic pressure groove.

9. according to claim 1,8 described in the middle of the rotating ring mechanical seal device, it is characterized in that: the groove depth of the fluid dynamic pressure groove that is provided with on the end face can be that deep trouth also can be a shallow slot, and its scope is between 0.1 micron～3 millimeters.

10. according to claim 1,8,9 described in the middle of the rotating ring mechanical seal device, it is characterized in that: the grooved of the fluid dynamic pressure groove that is provided with on the end face can be spiral chute, arc groove, "T"-shaped groove, straight-line groove, also can be the combination of various grooveds.

11. according to claim 1,7 described middle rotating ring mechanical seal device, it is characterized in that: the stationary ring (1) of middle rotating ring (2) and both sides thereof and rotating ring (4) are formed primary seal.

12. according to claim 1,7,11 described middle rotating ring mechanical seal device, it is characterized in that: the layout of sealing can be the single-stage sealing, also can be tandem seal or double seals.

13. according to claim 1,7,11,12 described middle rotating ring mechanical seal device is characterized in that: in the multi-stage sealed layout, can be the combination seal that middle rotating ring sealing forms with other form motive sealing.

14. rotating ring mechanical seal device in the middle of according to claim 1, it is characterized in that: sealed medium and employed obstruction fluid can be that gas also can be liquid.

15. the rotating ring mechanical seal device is characterized in that: can be that mechanical seal with inward leakage also can mechanical seal with outward leakage in the middle of according to claim 1.

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