SU1087729A1 - Shaft seal - Google Patents

Abstract

1. A shaft seal made in the form of a floating ring of elastic material located in the bore of the housing, enclosing the shaft and forming an annular channel with the housing to which the sealing medium supplied to the inner part of the floating ring along the radial channels, characterized by In order to increase F14g.1 of its reliability, an annular bore is made on the inner surface of the floating ring, in which a sleeve of porous material is rigidly mounted, forming a ring with a floating ring -hand chamber into which said radial channel output. 2. Sealing according to claim 1, characterized in that, in order to reduce the flow rate of the sealing medium, the porous sleeve is made of two parts of different permeability, with a part of the sleeve of lower permeability located on the side of the cavity of lower pressure. 3. Seal on PP. 1 and 2, characterized in that the inner diameter of the annular portions of the floating ring is made equal to the inner diameter of the porous sleeve.

Description

The invention relates to mechanical engineering, in particular to seals of rotating shafts, and is intended primarily for sealing liquid vapors using barrier gases.

A shaft seal is known, made in the form of a floating ring, located in the bore of the housing, enclosing the shaft and forming an annular channel with the housing, to which the sealing fluid is supplied under pressure to the inside of the floating ring through the radial channels 1.

However, when working on compressible sealing media (gases), the known compaction is characterized by a deterioration in the "tracking of fast radial movements of the shaft, as well as the occurrence of self-oscillations of the floating ring. The source of faults is relatively large volumes of compressible densified medium enclosed in chambers.

The object of the invention is to increase the reliability as well as reduce the flow rate of the sealing medium.

The goal is achieved in that in the shaft seal, made in the form of a floating ring of elastic material, located in the bore of the housing, grasping the shaft and forming an annular channel with the housing, to which the sealing medium supplied to the inner part of the floating ring along radial channels , an annular bore is made on the inner surface of the floating ring, in which a sleeve of porous material is rigidly mounted, forming an annular chamber with a floating ring in which enes said radial ducts.

In this case, the porous sleeve is made of two parts of different permeability, with a part of the sleeve of lower permeability located on the side of the cavity of lower pressure.

In addition, the internal diameter of the ring sections of the floating ring is made equal to the internal diameter of the porous sleeve.

FIG. 1 shows the seal, a general view in section; in fig. 2 shows a seal version with a porous bushing consisting of two parts; in fig. 3 - seal option

With annular portions of the floating ring whose inner diameter is equal to the inner diameter of the porous sleeve.

The shaft seal contains a floating ring 1 located in the bore of the housing 2, enclosing the shaft 3 and forming an annular channel 4 with a housing to which the barrier gas supplied to the inner part of the floating ring through radial channels 5 is supplied under pressure.

The internal part of the floating ring has a bore, in which the sleeve 6 of porous material is rigidly mounted, forming an annular chamber 7 with the floating ring, into which the radial channels 5 are led.

The porous sleeve can be made of two parts 8 and 9 (Fig. 2) with different permeability. The ring sections 10 and 11 (FIG. 3) of the floating ring can be made with an internal diameter, equal to Q and the internal diameter of the porous sleeve, and the lengths of these sections can be unequal.

Seal works as follows.

When the barrier gas is supplied to the seal under pressure, the floating ring 1 5 "is weighed relative to the shaft 3 due to the gas-static centering force. This force is due to the uneven pressure of the gas in the porous bushing in the circumferential direction: a higher pressure corresponds to the region of a smaller gap between the bushing and the shaft. The tracking of the floating ring over the movement of the shaft in dynamics, as well as the suppression of self-oscillations, is ensured by the absence of chambers on the inner surface of the seal.

The proposed seal is promising for use as an auxiliary in sealing assemblies for sealing liquids with flammable or explosive, as well as toxic fumes. Such seals have advantages over double face seals when the barrier fluid does not enter the sealable medium.

The use of the proposed seal in conjunction with a single mechanical seal makes it possible to completely eliminate the ingress of harmful vapors or the liquid itself into the atmosphere, increase the reliability of the pump sealing unit and reduce operating costs.

Fig.Z

eight

Claims (3)

1. SHAFT SEAL, made in the form of a floating ring of elastic material located in the bore of the housing, grasping the shaft and forming an annular channel with the housing, to which the shutter medium is supplied under pressure, supplied to the inner part of the floating ring through radial channels, characterized in that in order to increase Figure 1 of its reliability, an annular bore is made on the inner surface of the floating ring, in which a sleeve of porous material is rigidly mounted, forming an annular chamber with the floating ring, into which these radial channels are discharged. 2. Seal by π. 1, characterized in that, in order to reduce the flow rate of the gate medium, the porous sleeve is made of two parts of different permeability, and part of the sleeve of lower permeability is located on the side of the cavity of lower pressure. 3. The seal according to paragraphs. 1 and 2, characterized in that the inner diameter of the annular sections of the floating ring is made equal to the inner diameter of the porous sleeve.