RU1827487C - Shaft seal - Google Patents

Abstract

Usage: in hydro- and turbomachinery. SUMMARY OF THE INVENTION: the main and additional nonrotating sealing rings are installed in the housing and the rotating sealing rings are mounted on the shaft. The rotating ring is located in the bore between the non-rotating rings and forms throttling slots with them first and second along the working medium. Hydrochambers are made on the end surface of the rotating ring before the second throttling slot and communicated by channels with the first slot. Non-expanding rings are mounted in the housing with the possibility of axial movement and the formation of an unloading chamber with the spring element therein from the side of the low pressure cavity. The discharge chamber is connected to the high pressure cavity by peripheral channels formed on the outer surfaces of the non-rotating rings. On the sealing surfaces of the slots, blind pockets are made. The height of the first slit is made decreasing with increasing diameter. 1 s, par. F-ly, 2 ill. Joint venture

Description

The present invention relates to hydro and turbomachinery. namely, rotary shaft seals.

The purpose of the invention is to increase the reliability of the shaft seal by improving the stability of the position of the rotating ring in the throttling slots of the non-rotating sealing rings.

The indicated goal is achieved by that. that in the foreign construction of the shaft seal containing the main and additional non-rotating sealing rings installed in the housing and the rotating sealing rings on the shaft, the latter being placed in the bore between the non-rotating rings assembly and forms the first and second along with them

working medium, throttling slots and pockets made on the end surface of the rotating ring in front of the second throttling slot and communicated by the channels with the first throttling slot, according to the invention, non-rotating sealing rings are mounted in the housing with axial movement and form a low-pressure cavity therefrom an unloading chamber, in which the spring element is placed, and connected to the high-pressure cavity by means of peripheral channels made on the outer surfaces of the neural lining rings, and blind pockets are provided on the sealing surfaces of the throttle slots.

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Thus, the proposed design of the shaft seal has the following significant distinguishing features:

- non-rotating sealing rings are mounted in the housing with the possibility of axial movement, which makes it possible to stabilize the position of the rotating sealing ring during operation and maintain the optimal value of the first and second throttling slots;

Non-rotating sealing rings form an unloading chamber with a housing on the side of the low-pressure cavity in which spring elements are placed, which allows hydraulic unloading of a pair of non-rotating rings and. thereby simplify the adjustment of the size of the gaps of the throttling slots, i.e. improve sealing performance;

- the discharge chamber is connected to the high-pressure cavity by means of peripheral channels formed on the outer surfaces of the non-rotating rings, which allows the supply of a high-pressure medium to the opposite end of the pair of non-rotating sealing rings and provides hydraulic discharge of the seal;

-between the flow pockets on the end surface of the rotating sealing ring additional blind pockets are fulfilled, which makes it possible to strengthen the damping role of the sealing gap and allows the self-installation of the rotating sealing ring during operation:

- blind pockets are made on the sealing rings in the region of the first throttling gap, and their design is selected in such a way that the total throttle gap area decreases with an increase in diameter,

Figure 1 shows the proposed shaft seal construction, longitudinal section; figure 2 is a section aa in figure 1.

The shaft seal contains the main rings 2 installed in the housing 1 and the additional 3 O-rings that are non-rotating on the shaft 4 and 5 rotating, the latter being placed in the bore 6 between the non-rotating rings 2 and 3 assembled and forms with them first 7 and second 8 along the working medium throttling slots, and pockets 9, made on the end surface 10 of the rotating ring 5 in the region of the agro-throttling gap 8 and communicated by the channels 11 with the first throttling slot 7. The non-rotating rings 2 and 3 are installed in the housing 1 with the possibility of axial per displacements and form therewith a cavity 12 from a low pressure discharge chamber 13, associated with the cavity 14, a high pressure through the peripheral channels 15 formed on the outer surfaces of the rings 16 nevraschayuschihs 2m 3. The discharge

chamber 13 contains spring elements 17, for example, in the form of helical springs, pressing an additional non-rotating ring 3 to the end surface 10 of the rotating ring 5. The torque is transmitted from the shaft 4 to the ring 5 by a pin 18, and this ring is sealed relative to the shaft by a secondary seal twenty.

In addition, on the end surfaces forming the 1st throttle gap, the rotating 5 and the main non-rotating 2 rings, or at least one of them has blind pockets 19, and their configuration is selected so that with increasing diameter, the height of the throttle gap decreases , i.e. the condition is satisfied

- d -do + n (bi hi) Jif (d + Ad) 5о + n (bt + 1 hi + 1)

where d and Ad are the current diameter and its increment; n is the number of pockets; bi and Li-1 - pocket width, respectively, on the diameters d and d I-Ad; h and s + 1 - depth of pockets. Moreover, between the flowing pockets 9 on the end surface 10 of the rotating sealing ring 5, additional blind pockets 21 (not shown) are made.

The shaft seal according to the invention operates as follows.

In the starting operation mode, the non-rotating additional ring 3 is pressed by means of spring elements 17 to the end surface 10 of the rotating ring 5. Non-rotating

rings 2 and 3 are unloaded at the same time, because the pressure of the working medium in the discharge chamber 13 and the pressure in the high-pressure cavity 14 are adjusted due to its free flow from the cavity 14 to the chamber 13

peripheral channels 15.

With increasing pressure in the cavity 14, the working medium passes through the first throttling slot 7 and the channels 11 enter the pockets 9 and 21, and then through the throttling gap 8 it enters the low pressure cavity 12. In this case, the rings 3 assembled with the ring 2 moves towards the cavity

12 low pressure, compressing the spring elements 17. to establish a stable position of the rings 2 and 3 relative to the rotating sealing ring 5 and, accordingly, to achieve the optimal (calculated) ratio of the gaps in the first 7 and second 8 along the flow of the working medium of the throttling slots. With any change in the forces acting on the rings 2 and 3, the sealing gaps in the slots 7 and 8 are automatically maintained due to the restoring force, returning the rings 2 and 3 to their original position and providing their hydraulic unloading.

To ensure the stability of the flow of the working medium in the first throttle slot 7 (flow from the center to the periphery), blind pockets 19 are made on the end surface of the ring 5 or (and) the main non-rotating ring 2, and their geometry is selected so that with increasing diameter the total area the throttle gap decreases. This can be achieved either by reducing the width H of the pocket or by reducing its depth hi, or together.

Maintaining the optimal value of the sealing gaps in the first 7 and second 8 throttling slots contributes to the execution on the end surface 10 of the rotating sealing ring 5

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Claims (2)

1. A shaft seal containing the main and additional non-rotating and sealing rings installed in the housing, the latter being placed in the bore between the non-rotating rings and forming the first and second throttling slots with them along the working path, and hydraulic chambers made on the end face rotating rings in front of the second throttling slot to communicated channels with the first throttling slot, characterized in that the non-tearing sealing rings are installed in the housing with the possibility of axial displacement and the formation of the housing from the side of the low-pressure cavity, the unloading chamber, in which the spring element is placed, the unloading chamber is connected to the high-pressure cavity by means of peripheral channels made on non-rotating rings of the outer surfaces. 2. The shaft seal according to claim 1, including the fact that blind pockets are made on the sealing surfaces of the throttle slots, the height of the first Q of the throttle gap is made decreasing with increasing diameter. 0 5 fie / sixteen  I - & (pt / s. 2.