SU1404731A1 - Rotating shaft seal - Google Patents

Abstract

The invention relates to a sealing technique, in particular to shaft seals with floating rings. The purpose of the invention is to increase the reliability of the sealing operation by allowing adjustment of the clearance between the outer ring and the sleeve. The seal consists of a housing in which floating outer and inner rings are located, installed with sealing gaps relative to the sleeve fixed on the shaft. In the housing there is a channel for supplying a condensed fluid. In the outer floating ring on the end surface there is a groove with a depth determined by calculation. During the operation of the seal, the force arising due to the pressure difference bends the annular shank of the outer ring formed by the groove, adjusting the gap between the ring and the sleeve. 2 Il. (L

Description

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The invention relates to sealing technology, in particular to shaft seals with floating rings.

The purpose of the invention is to increase the reliability of compaction by. Ensuring that the gap between the outer ring and the tulk is constant.

Fig. 1 illustrates the proposed sealing, and Fig. 2 shows a scheme for changing the gap between the outer floating ring and the hub.

The seal consists of a housing 3, in which there are floating outer 2 and inner 3 rings installed with sealing gaps 4 and 5 relative to the sleeve 6 fixed to the shaft 7. To prevent gas from breaking in the gaps between the shaft 7 and the sleeve 6, as well as the end surface The inner ring 3 and the housing 1 are fitted with rubber rings 8 and 9. The floating rings 2 and 3 are secured against rotation by pins 10 and are pressed by the point springs 11, the outer ring 3 is filled with self-adjusting pads 12, and on the inner one A floating ring 3 is an annular groove 13 for equalizing pressure around the circumference of the ring. In the outer floating ring 3, an annular groove 14 is made on the end surface, with a depth of X determined by calculation, in case 1 there is an opening 15 for supplying sealing fluid.

The seal of the rotating shaft works as follows.

The sealing fluid with a pressure exceeding the pressure of the compressed gas by 3-5 10 Pa, through the opening 15 in the seal housing enters the cavity between the floating rings 2 and 3 and moves in two directions. A small part of the liquid enters the sealing gap 5 between the sleeve 6, mounted on the shaft 7, and the internal floating ring 3, then flows into the chamber, where it mixes with the gas to be compacted and discharged into the oil separator. A larger flow of sealing fluid enters the gap 4 between the outer ring 2 and the sleeve 6 and is discharged into the oil sump. When the compressor shaft rotates due to hydrodynamic friction in the sealing gap 5, due to its small size (0.03-0.06 mm), large

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The amount of heat. A minor part of the heat is removed along with the flow of sealing fluid through the gap 5 towards the chamber MG. The rest of the heat goes to the heating of the inner ring and the temperature of the sealing fluid.

The gap 4 is selected so as to absorb through it the main part of the heat released in the gap 5 with the main fluid flow. The size of the gap 4 is 1.5-2 times the size of the sealing gap 5 and is in the range of 0.06-0.12 mm. The annular groove 14 provides a constant design value of the gap 4 between the ring 2 and the sleeve 6, the flow of sealing fluid and the maximum heat removal during compaction of gas with high and ultrahigh pressure. The force resulting from the pressure difference (in the gap 4, the pressure exceeds atmospheric, and the annular groove communicates with the atmospheric pressure cavity), bends the annular tail formed on the ring by the groove in the direction of the annular groove and allows you to select the depth of the groove by calculation, adjust the gap between outer floating ring 2 and sleeve 6.

Thus, making an annular groove on the toric surface of the outer floating ring ensures the constancy of the gap between the ring and the sleeve mounted on the shaft due to the elastic deformation of the annular shank and creates better conditions for heat removal from the gap of the inner ring. This makes it possible to withstand the design value of the temperature of the sealing fluid in the gap of the inner ring, thereby reducing the flow of fluid into the working cavity of the compressor, increasing the hydrodynamic centering force of the inner ring, reducing its wear and increasing the service life of the seal assembly. The eccentricity of the shaft in the inner ring is also reduced, thereby preventing the risk of gas breakthrough from the compressor cavity to the seal.

Claims (1)

Invention Formula The seal of the rotating shaft, comprising a housing, an inner and an outer, floating rings installed with sealing gaps relative to the sleeve mounted on the shaft, and the outer floating ring is made with self-aligning pads with clamps from their circumferential rotation, which, in order to improve the reliability of the seal by ensuring the clearance between the outer ring and sleeve, on the end surface of the outer floating ring is made annular groove depth X, defined by the formula  y - t l p H.k rt where X is the depth of the groove; RP - pressure on; breakdown of sealing fluid; Py is the pressure in the section located at a distance to from the ring end;  outer ring length ten I 1 Fie.2