RU2719753C1 - Brush seal - Google Patents

Abstract

FIELD: machine building.SUBSTANCE: invention relates to machine building and can be used for compaction of air, gas or oil cavities. Brush seal comprises an annular bracelet-brush installed on the stator, consisting of thin metal wires, and a bushing which is installed on the rotor opposite to the radial brush, wherein bracelet-brush wires are laid in plane perpendicular to rotational axis in radial direction and fixed in annular metal cartridge, and wires forming wire brush are bent in form of evolvent.EFFECT: technical result consists in provision of reliable sealing of cavities between rotating and fixed elements of structure of various mechanisms operating including in conditions of high temperatures.3 cl, 3 dwg

Description

The invention relates to mechanical engineering and can be used in any device where it is necessary to eliminate or reduce the leakage of the medium being sealed from one cavity to another, located between the structural elements. The device can be used to seal air (gas) or oil cavities.

To seal the cavities located between the structural elements, brush seals have become widespread. When compacting the cavities, the task is to eliminate or significantly reduce the leakage of the medium being sealed from one cavity to another. In this case, overflows arise not only through the gap between the parts of the mechanism, but also through the structural elements of the seal. Overflows through the gap can be reduced by reducing the size of the gap. And the flow through the design elements of the brush seal - through the wires forming the brush - reducing the gap between these wires.

A sealing device for a high-pressure turbine of a turbomachine (RU 2296866) is known, comprising a brush seal formed by elastic sealing fibers, each fiber having a main section and a second section connected by a curved section, characterized in that it further comprises a flexible gasket curved in cross section, which has a free an end that abuts simultaneously the fibers of the brush seal and the sealing surface so that the ends of the fibers of the brush seal are constantly in contact with the seal yaemoy surface.

The design of such a device has the following disadvantages: the sealing fibers are laid arbitrarily, which leads to the appearance of gaps between the fibers at different radii of these fibers and does not provide reliable sealing of the cavities. In addition, the presence of additional elements, such as flexible gaskets, complicates the design and increases the cost of production of such seals.

Known multi-rod brush seal assembly for rotor installations (RU 2309314), containing an elongated brush rod holder, at least three elongated brush rod blocks, tightly joined together in said brush rod holder, forming a single unit, while many brush rod blocks are tightly connected staggered in the holder of the brush rods, each said brush rod block comprising a bristle holder and a plurality of bristles connected to the bristle holder.

The design of such a brush seal has the following disadvantages:

The seal bristles are located in the holder without bending the bristles themselves, which inevitably leads to gaps between the bristles at different radii of the bristles and does not provide reliable sealing of cavities due to leaks of the medium being sealed between the bristles. In addition, this design requires a lot of space for installation, which significantly limits the possibilities of its application.

Known for the prototype is a dynamic brush seal (RU 2454558) formed by non-metallic bristles, containing a casing for bristles, mounted on the rotor or on the stator and characterized in that the bristles are supported on the stator or rotor with an inclination from the sealing side with lower pressure.

The design of such a seal has the following disadvantages:

The sealing bristles are laid in a tangential direction arbitrarily, which inevitably leads to the appearance of gaps between the bristles at different radii of the bristles and does not provide reliable sealing of cavities due to leaks of the sealing medium between the bristles. In addition, the use of non-metallic bristles does not allow the use of such a seal at high temperatures.

The technical result, which consists in ensuring reliable sealing of cavities between rotating and stationary structural members of various mechanisms, including those operating at high temperatures, is achieved by the fact that according to the invention, the brush seal comprises an annular brush bracelet mounted on a stator, consisting of thin metal wires, and a sleeve that is mounted on the rotor opposite the radial brush, and the wires of the bracelet-brush are laid in a plane perpendicular to the axis of rotation in the radial direction and fixed in an annular metal cage, while the wires forming the brush are bent in the form of an involute.

An involute has the property of constant distance (including zero) between two identical curves (involutes) along these involutes themselves, constructed from one center and one radius. If the bracelet-type seal wires are laid in a circle in a radial direction in the plane of the perpendicular axis of the rotor, then the minimum (including zero) clearance, and, therefore, the minimum leakage of the medium to be sealed between the wires, is provided when these wires are bent only in the shape of the involute. Thus, the bending of the wires along the involute allows you to minimize the gap between the individual wires up to zero.

The invention is illustrated by drawings:

FIG. 1 - brush seal with an annular bracelet,

FIG. 2 - brush seal with an annular bracelet from two rows,

FIG. 3 - brush seal with an annular bracelet in the form of two rows of separate segments

Where

1 - wire brush;

2 - clip;

3 - sleeve.

The brush seal is designed to minimize the leakage of the medium being sealed from one side of the seal to the other and contains a ring brush-bracelet installed on the stator, consisting of thin metal wires, and a sleeve that is mounted on the rotor opposite the radial brush. Ring bracelet-brush includes a clip 2 with a wire brush 1 and is mounted on the stator. And on the rotor opposite the wire brush 1 is installed sleeve 3.

Under the action of the pressure differential between the sealing cavities, the medium being sealed flows through the gap between the wire brush 1 and the sleeve 3, as well as through the gaps between the wires of the brush 1. Minimization of the flows is achieved by reducing the gap between the brush 1 and the sleeve 3, as well as by reducing the gap between individual wires, which in turn is achieved due to the bending of the brush wires in the form of an involute and the installation of these wires in a clip with a minimum (up to zero) clearance.

The crossflows through the gap between the brush 1 and the sleeve 3 are determined by the pressure difference between the cavities and the size of this gap, i.e. design features of the device in which the seal is installed. Bending the brush wires in the form of an involute and mounting these wires in a ferrule 2 with a minimum (possibly zero) clearance can significantly reduce the flow of the medium being sealed through the gaps between the wires of the brush 1 and, therefore, reduce the total total flow of the medium being sealed through the seal assembly.

Claims (3)

1. A brush seal comprising a ring bracelet-brush mounted on a stator, consisting of thin metal wires, and a sleeve that is mounted on the rotor opposite the radial brush, and the wire of the brush-bracelet is laid in a plane perpendicular to the axis of rotation in the radial direction and fixed in an annular metal clip, characterized in that the wires forming the brush are bent in the form of an involute. 2. Brush seal according to claim 1, characterized in that the annular bracelet is made in the form of a combination of individual segments. 3. The brush seal according to claim 1, characterized in that the annular bracelet is made of two or more rows.

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