SU785575A1 - Direct-flow labirinth packing - Google Patents

Description

(54) RECTIFIED LABYRINTH SEAL

Iobrebragonie refers to the sealant: heat engineering, in particular to npHtvio exact labyrinth seals of rotating shafts.

A straight-flow labyrinth seal is known, which is a set of annular discs (crests) sequentially installed in the casing, whose inner edges alternate with the shaft to form labyrinth enclosures 1.

The disadvantage of it is a large leakage environment.

The purpose of the invention is to reduce steam leakage by creating. secondary flow directed against the main flow,

To do this, in the sealing housing, over the last annular disk, an annular chamber is provided with supply channels from the flow-through part of the sealing and openings, the axes of which are inclined from this chamber toward leakage. Above the penultimate ring disc, a similar annular chamber is made.

FIG. 1 shows the proposed cross-sectional seal} in FIG. 2 - annular chamber.

The seal consists of a housing 1 and, on which the annular disks 3 are fixed, forming labyrinth slots with the inner surface of the housing. The discharge channel 4, through which the working medium from chamber 5 is fed into the exact part of the seal, is located at an angle oL 30-45 to the generator of the inner surface of the seal body. In case 1 is made, also pots15 vodgatsy channel 6.

The sealing operation is as follows. The steam expanded in the gap enters the last annular disk. The direction of the main flow is shown

Claims (1)

20 by the arrow A. A part of steam through the feed channels 6 enters the annular chamber 5 located in the seal housing 1 above the last annular disk. 37 From chamber 5, through the discharge channel 4, a vapor stream is fed into the zone preceding the last annular disk. As a challenge. The channel is inclined, the vapor flow coming out of chamber 5 is directed oppositely to the main flow, i.e. from the camera towards leakage. The interaction of the fluxes leads to a decrease in the velocity of the main flux and to an increase in the hydraulic resistance, and then: to a decrease in leakage. The greatest effect is achieved with the following parameters: 0.02-0.05; I 0,2 - 0, f f 4- / j4 i, 0.8-1 8, d is the diameter of the supply channel; D is the diameter (of the inner surface of the housing; 6 is the width of the TIP DIRECTIONAL channel: clearance in the seal; X offset of the axis of symmetry of the discharge channel relative to the disc input edge; "g is the thickness of the annular disc the leakage level can be ensured if the same chamber 5 as above the last annular disk is formed over the penultimate annular seal disk and in the penultimate contraction to form a secondary flow with it, just as it was done earlier. Looping does not limit the movement of the rotor relative to the body, its axial dimensions remain perfectly unchanged. Claim 1, The first motor labyrinth seal, made in the vice ring rings, which are successively installed in the body seal, and the edges of which form with the shaft This is due to the fact that, with a reduced steam leakage, in the casing and over the last annular disk, along the leakage path, an annular chamber with inlet channels from the downstream part of the seal and by diverting the channels, the axes of which are inclined from the chamber towards the leakage, at that the following ratios are observed: 5 - 0.02-0.05; - 0.2-0.4, 0.8-1.8, (5 - diameter of the inlet to the shaft; X - diameter of the inner surface of the body; - width of the discharge channel; g gap in seal X - offset the axis of symmetry of the retrac- tion channel relative to the upper edge of the disk; the thickness of the annular aisy 2 "The seal, according to claim 1, that is, above the penultimate annular. formations taken into account during the examination I. Shcheglov A, B, Steam turbines, M., Energia, 1967, pp. 159, fig, 6.8, / 77777777 / 77777777Г / 77У /; 7 // 7 /// у / У; //////// 7 / р /// U ///// /; / FIG. 1, HHCHCHCHEHPHCHCHCHCHCHC 785575 (Rig.2