RU1410612C - Face seal - Google Patents

Abstract

The invention relates to a sealing technique, namely, mechanical seals for pumps. The purpose of the invention is to expand the range of applications for mechanical seals by reducing the axial forces acting on the shaft from the differential pressure to be sealed. In the mechanical seal separating the cavities 3 and t of high and low pressure and formed by friction rings 5j 6, chambers 1, 16 are formed by installing additional friction rings 12, 13. When communicating chambers 1b with a high-pressure cavity 3, and chambers 1 t - with a cavity (low pressure there is an axial force acting on the shaft and a compensating force from the action of the pressure being sealed on the shaft.-1 c.p.

Description

The invention relates to a sealing technique, in particular a mechanical seal. seals, and can be used in the construction of mechanical seals for pumps pumping working fluid at high pressure levels.

The aim of the invention is to expand the field of use of mechanical seals by reducing the axial forces on the sealing shaft from the sealing pressure during operation.

Figure 1 shows the proposed mechanical seal, section; Fig. 2 is the same embodiment.

Face 5 shaft seal 1 mounted on the housing 2 between the high pressure cavity 3 and the low pressure cavity 4 is formed by a non-rotating ring, friction S and a rotating friction ring 6 located on the end 7 of the annular protrusion 8 on the shaft 1. At the opposite end 9 of the annular protrusion 8, additional friction rings 10 and 11 are fixed, forming together with the non-rotating friction rings 12 and 13 a chamber lA communicating with channel 15 with a low pressure cavity, and a chamber 1b formed by friction rings S and 13 is communicated by channel 17 with a cavity 3 high who pressure.

A mechanical seal embodiment is possible in which additional friction pairs are located on the side of the low pressure cavity i. In this case, the chamber formed between the additional friction rings 12 and 13 is in communication with the high-pressure cavity 3 by the channel 18, and the chamber formed by the friction rings 6 and 12 is in communication with the low-pressure cavity by the channel 19.

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about

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Sealing works as follows.

When a pressure differential occurs on the main friction pair formed by friction rings 5 and 6 between cavities 3 and high and low pressure, an axial force arises on the shaft, due to the dimensions of shaft 1. The presence of channels 15 and 17 (Fig. 1), channels 18 and 19 (Fig. 2) and mechanical seal chambers I t, 16 provide axial force acting on the annular protrusion 8 of the shaft 1 in the direction opposite to the pressure drop on the main friction pair formed by friction rings 5, 6. When performing the diameter of the outer additional ring tr e-. not 13 according to the relation d,

;

external do, full unloading occurs

shaft due to axial force arising from the action of the sealing pressure.

For example On the main friction pair with an average diameter of mm and a pressure drop of MPa, the force acting on the mechanical seal shaft is 650 kN. When performing mechanical seal with an additional chamber, the average diameter of the external additional ring is determined from the ratio Dng d, - {T and is / 339 mm, the force due to the communication between the cavities is equal

 -

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A 3

op & r

de AR - sealing differential pressure,

F is the force acting in the opposite direction to the action of the pressure being sealed;

the average diameter of the outer additional friction ring; Djj is the average diameter of the inner friction ring.

js

0

5

0

5

0

5

0

5

When calculating the resulting F -r | - (0.3392 - 0,). 6.50 kN.

Thus, a complete unloading of the seal occurs due to the axial force acting on the shaft from the seal differential pressure.

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Claims (2)

1.A mechanical seal comprising a housing and a friction pair located therein, consisting of a non-rotating friction ring, pressed against the friction surface at the end of the annular protrusion on the rotating shaft from the low pressure side, characterized in that, in order to expand, range of use is sealed and, it is equipped with additional friction pairs formed by rings placed between the non-rotating body and the end face of the annular protrusion on the shaft from the high pressure side, and channels are made in the housing and in the protrusion on the shaft, m cavity between additional pairs of frictional channel communicates in a projection on a shaft with a low pressure cavity, and the cavity between the outer core and the additional pairs of frictional channel communicates with the cavity in the housing high pressure. 2. The seal according to claim 1, characterized in that, in order to completely compensate for the axial force acting on the shaft from the pressure being compressed, the diameters of the main friction ring and the inner additional friction ring are equal, and the diameter of the outer additional friction ring is made according to the ratio g, d., where dg is the average diameter of the inner additional friction ring,, is the average diameter of the outer additional friction ring. F.