RU2303731C1 - Rotary shaft seal - Google Patents

Abstract

FIELD: sealing equipment, possible use for sealing rotary shafts in designs of compressors, gas and steam turbines, pumps and other centrifugal rotor machines.

SUBSTANCE: seal contains a body, with a rotary valve passed through it. External and internal floating rings are mounted on the valve with packing gaps. Inside the external floating ring, reverse self-mounting damping blocks are positioned on hydrostatic film, and between blocks reverse scrapers made of anti-burring current-conductive material are mounted. The internal floating ring is suspended in radial direction on a spring device, positioned in direction of gravity force effect. Internal surfaces of external and internal floating rings have anti-friction cover, separated in the direction of flow of make-up substance by grooves having a single row of holes. Floating rings contact the body with sealing belts which have wear-resistant cover. A plate with wear-resistant cover is mounted in the body. Seal is made with minimal leaking of make-up liquid, ensuring reliable localizing of external ring and damping of centrifugal machine rotor, preventing electro-chemical corrosion of internal anti-corrosion cover of floating rings, facilitating suppression of transverse oscillations of rings and ensuring minimal wear of packing end belts, also making it possible to prevent dry contact of internal floating ring with the shaft and to prevent burn-on during launching modes.

EFFECT: increased efficiency.

2 cl

Description

The invention relates to a sealing technique and can be used to seal rotating shafts in the construction of compressors, gas and steam turbines, pumps and other rotary centrifugal machines.

A rotating shaft seal is known, comprising a main mechanical seal, the movable contact of which is formed by the elements of the stationary and rotating nodes interacting along the sealing belt. The rotating assembly is made in the form of a holder with an antifriction ring. The auxiliary gap seal and the main mechanical seal are separated by a shutter chamber. The auxiliary gap seal has at least two floating rings, each of which is installed in a separate housing and is in contact with an end sealing belt. Moreover, each floating ring is suspended in a radial direction on springs placed in two mutually perpendicular planes at an angle of 45 ° to the direction of gravity [RF patent for the invention No. 2170864, F16J 15/34, 2001].

The specified rotation shaft seal has the following disadvantages:

- insufficient centering of the rings and damping of the rotor of the centrifugal machine;

- insufficient prevention of electrochemical corrosion of the internal antifriction coating of floating rings;

- the presence of transverse vibrations of the rings;

- insufficient warning of burns during start-up conditions;

- quite a lot of wear on the end sealing belts.

The basis of the invention is the task to eliminate these disadvantages and to create a seal of the working cavity with minimal leakage of the barrier fluid.

The problem is solved by the fact that in the seal of the rotating shaft containing the housing through which the rotating shaft passes, on which the outer and inner floating rings are installed with sealing gaps, the sealing belts in contact with the housing, the inner surfaces of the floating rings have an antifriction coating, and the inner floating ring suspended in a radial direction on a spring device according to the invention, reversible self-aligning dampers are located inside the outer floating ring pads on a hydrostatic film, between which reversible scrapers of anti-seize conductive material are installed, the antifriction coating of the inner surfaces of the floating rings is divided in the direction of the flow of the gate medium by grooves containing a single row of holes, the end sealing belts have a wear-resistant coating, a plate with a wear-resistant coating is installed in the housing, and the spring device is placed in the direction of gravity.

The installation of reversible self-aligning blocks on an hydrostatic film inside the outer floating ring ensures reliable centering of the outer ring and damping of the rotor of the centrifugal machine. Reversible self-aligning pads ensure operability regardless of the direction of rotation of the shaft.

Placement of reversible scrapers of anti-seize conductive material between the reversible self-aligning blocks, which act as current collection brushes, allows to reduce static electricity from the shaft and prevent electrochemical corrosion of the internal anti-corrosion coating of floating rings.

The separation of the antifriction coating of the inner surfaces of the floating rings in the direction of the flow of the gate medium by grooves containing a single row of holes helps to break up the annular vortex of the gate fluid formed under the action of friction and rotational motion of the shaft. Thus, the holes contribute to damping the lateral vibrations of the rings.

Installation of a plate with a wear-resistant coating in the housing ensures minimal wear on the end sealing belts.

Placing the spring device on which the inner floating ring is suspended in the direction of gravity helps to compensate for the mass of the inner floating ring and the friction force in the end joint of the sealing belt, which, in turn, prevents dry contact of the inner floating ring with the shaft and, as a result , burns during start-ups. During operation, such compensation allows using the hydrodynamic centering force, which ensures concentricity of the sealing gap, with maximum effect.

The invention is explained by the drawings.

Figure 1 shows a longitudinal section of a seal of a rotating shaft;

figure 2 is a section along aa of figure 1.

The seal of the rotating shaft contains a housing 1 through which the rotating shaft 2 passes. On the shaft 2, outer 3 and inner 4 floating rings are installed with sealing gaps.

Inside the outer 3 floating rings are located reversible self-installing damper pads 5 on a hydrostatic film, between which reversible scrapers 6 are made of anti-seize conductive material. The inner 4 floating ring is suspended in a radial direction on a spring device 7 located in the direction of gravity. The inner surfaces of the outer 3 and inner 4 of the floating rings have an anti-friction coating 8, divided in the direction of the flow of the gate medium by grooves 9 containing a single row of holes 10. The floating rings 3, 4 are in contact with the housing by sealing belts 11 having a wear-resistant coating. In the housing 1, a plate 12 with a wear-resistant coating is installed.

Between the inner 4 floating ring and the housing 1 is placed a chamber 13 for supplying a locking fluid connected through grooves 14, an annular groove 15 and the holes 16 of the inner 4 floating ring with a cavity 17 between the floating rings 3, 4.

The seal of the rotating shaft operates as follows.

The shutter fluid under a pressure higher than the pressure in the working cavity 18 is fed into the supply chamber 13. From the supply chamber 13 through the grooves 14, the annular groove 15 and the openings 16 of the inner floating ring 4, the shutter fluid enters the cavity 17, creating a hydraulic shutter and preventing leakage of the sealing environment into the atmosphere.

Claims (1)

A rotating shaft seal comprising a housing through which a rotating shaft passes, on which the outer and inner floating rings are installed with sealing gaps and sealing belts in contact with the housing, the inner surfaces of the floating rings are antifriction coated, and the inner floating ring is suspended radially on a spring device , characterized in that inside the external floating ring are located reversible self-installing damper pads on a hydrostatic film, m By means of which reversible scrapers made of anti-seize conductive material are installed, the antifriction coating of the inner surfaces of the floating rings is divided in the direction of the flow of the gate medium by grooves containing a single row of holes, the end sealing belts have a wear-resistant coating, a plate with a wear-resistant coating is installed in the housing, and the spring device is placed in the direction gravity action.

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