RU2594835C2 - Brush sealing and method of its making - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: brush sealing is made as a pressing cheek and elements: the ring wire brush and the supporting cheek which are successively connected to it. At that the wire brush is made out of the alternating rows of wires with large and small diameters, wherein the wires with large and small diameters are tightly pressed to each other at the place of their securing, and are located in a staggered order, and the rows of wires making the brush are located in the planes crossing the axis of the sealed rotor. The method of manufacturing of the rotor brush sealing when along the sides of the mandrel support flanges are arranged, wire is wound, then the wire coil is swaged by pressing flanges, coinciding them with external cylindrical surfaces along the cutting surface of the wire coil, the wire coil is cut, then mated elements are welded along their external cylindrical surfaces, and final machining is performed, the wire is wound by alternating layers, first of all a layer of a large diameter wire, then on the made layer of a large diameter wire the layer of a small diameter wire is wound, wherein the layer of a small diameter wire is wound arranging the small diameter layer in the depressions made in the layer of a large diameter wire between adjacent wire turns.

EFFECT: invention improves the brush sealing tightness.

7 cl, 2 dwg

Description

The invention relates to a technology for the manufacture of seals and can be used in gas turbine construction, mechanical engineering, aircraft engine construction and other technical fields.

Improving the efficiency of gas and steam turbines is associated with improved designs and manufacturing techniques for radial gas-air duct seals, which can reduce the leakage of the working medium between the separated cavities. One of the promising types of seals is brush, which is a circular array of many closely spaced small-sized sealing elements - bristles (for example, RF Patent No. 2210694. IPC F16J 15/32. METHOD FOR MAKING BRUSH SEALS AND A DEVICE FOR ITS IMPLEMENTATION. Publ. 20.08.2003).

It is known that in order to ensure optimal sealing performance, the sealing elements (bristles) must be elastic enough to compensate for the radial clearance fluctuations in high vibration conditions, and the tightness should correspond to the value at which the power spent to overcome the friction force in one seal does not exceed 0.15% of the power consumed by the shaft at its maximum rotation.

A brush seal is known that contains an annular package of sealing elements that are free from one end and secured from the other, the gaps between which are filled with a fixing and sealing composition, the package being fixed between the side plates, and the sealing elements of the ring package made in the form of capillary tubes filled with antifriction material ( AS USSR No. 1725609. IPC F16J 15/16. BRUSH SEAL. Publ. 2005).

The disadvantage of this seal is the destruction of the sealant as a result of heating of the elements of the brush seal in contact with a rotating rotor, which increases the leakage of the working fluid and reduces the service life of the seal.

It is also known brush seal made in the form of a clamping cheek and sequentially docked with it elements - an annular wire brush and a supporting cheek, while the docked elements are made identical in outer diameter (AS USSR No. 1462916. IPC F16J 15/16. MANUFACTURE BRUSH SEALS. Published. 1996).

A disadvantage of the known devices is the increased leakage of the working fluid due to significant gaps between the wire bristles.

The closest technical solution to the claimed one is a brush seal containing bundles of wires placed around the circumference in the housing, located in a plane perpendicular to the axis of rotation of the shaft, and the wires are made of various materials. In this case, wires of a material with a high coefficient of thermal conductivity are located inside the beams, and wires of a material with a higher elastic modulus are located outside (AS USSR No. 1665136. IPC F16J 15/16. Brush seal. Bull. No. 27 1991) .

The disadvantage of this design is that the placement of wires from materials with different elastic modulus values in one bundle leads to uneven operation of the sealing elements and to an increase in the gaps between the bristles due to various plastic deformation of the elements made of different materials. As a result, the effect of wedging some bristles by others occurs, which reduces the tightness of the seal and leads to increased leakage of the working fluid.

The required degree of tightness of the cavities is provided by a certain number of tightly laid metal bristle wires in the gap of the pair being sealed. In one sealing stage, they are stacked one relative to another in several layers and form a rather wide layer of brush elements between the side plates. A possible embodiment of a small number of layers of metal bristles between the side plates of one stage, but then to ensure the required tightness of the cavities, a set of such elements is formed in several stages. An increase in the density and number of layers of bristles leads to an increase in the rigidity of the array of brush elements and, as a consequence, to excessive compression of the sealing surface, which reduces the power on the motor shaft and its life due to the rapid wear of the contacting pairs.

The objective of the invention is to increase the tightness of the brush seal and increase the service life of the rotor seal.

The problem is solved due to the fact that in the brush seal of the rotor, made in the form of a clamping cheek and elements sequentially docked with it - an annular wire brush and a supporting cheek, in contrast to the prototype, the wire brush is made of alternating rows of wires of larger and smaller diameters, and the wires larger and smaller diameters are tightly pressed against each other at the place of their fastening and are staggered relative to each other, and the rows of wires forming a brush are located in planes intersecting Referring compacted rotor.

In addition, the following brush seal options are possible: larger diameter wires in a row are tightly pressed against each other; wires of a smaller diameter, located in a row, are tightly pressed against each other; the docked seal elements are made identical in outer diameter, and the seal is equipped with a process ring placed on the docked elements made with a width corresponding to the total width of the said elements, and the clamping cheek is made with an end protrusion as a docking element, while its outer cylindrical surface is made for installation nest.

Since tightness is associated with the density of laying of metal bristle wires in the gap of the pair being sealed, and the bristles themselves must be sufficiently elastic and, at the same time, their total stiffness should not be excessive, then creating a composition of alternating bristle wires with larger and smaller diameters allows for sufficiently tight packing of the brush seal to reduce its total stiffness (i.e., prevent excessive compression of the sealing surface) by using bristle wires with less stiffness (with less m in diameter). In addition, the reduction in compression of the sealing surface also leads to an increase in the life of the seal by reducing the wear rate of the contacting pairs.

Many different methods are known for making brush seals from metal wires.

Thus, according to US patent (US Patent 6,505,835. F16J 15/32. Brush seals and methods of fabricating brush seals. 2003), the brush seal includes many bristles located in grooves. The method of fixing the bristles consists in placing them in the grooves of the sealing ring and fixing the bristles in these grooves by rolling.

However, such fixing of the bristles is not reliable and does not allow to form a high-tight seal, since the bristles are distributed unevenly in the form of brushes in the seal.

A known method of manufacturing a brush seal of rotors (US Patent 7,653,993. F16J 15/32. Method of manufacturing a brush seal for sealing between stationary and rotary components. 2010), including winding the wire onto a device that divides the wound wire coil into two parts, followed by welding and cutting the coil of wire with the formation of two packages of brush seals.

There is also a method of manufacturing a brush seal (RF patent No. 2210694, IPC F16J 15/32. METHOD FOR MAKING BRUSH SEALS AND A DEVICE FOR ITS IMPLEMENTATION. 2003), which consists in collecting a toroidal mandrel consisting of an annular base and two lateral ring clip. Next, in a usual way, wind the elastic material onto the mandrel, press it with annular cheeks, cut the elastic material along the outer diameter of the mandrel and fasten it with adjacent clip and cheek, and then cut the elastic material along the inner diameter to the required size. Before assembling the mandrel, lateral bevels are applied to the base, and inclined sections are made on the clips, in addition, coaxial holes are drilled on the peripheral part of the clips, then the base is placed between the clips so that the inclined sections of the clips are joined with the base bevels. Additionally, the clips are interconnected through drilled coaxial holes into which the fasteners are inserted, as a result of which the base and two clips form an integral mandrel. To fix the elastic material on the outer and inner annular surfaces of the mandrel, axial notches are applied on it. When cutting the elastic material along the outer circumference, the adjacent peripheral parts of the clips together with the fasteners are cut along with it. When cutting elastic material around the inner circumference, the adjacent part of the mandrel (base) is also removed. Lastly, adjacent clips are separated and the rest of the base is removed, resulting in two complete brush seal kits. The invention reduces the consumption of elastic material.

A disadvantage of the known methods is that they do not have a sufficiently wide range of functionality to ensure the formation of a brush seal with alternating layers of wire-bristles made of wires of larger and smaller diameters.

The objective of the invention is to expand the functionality of the method of forming a brush seal with alternating layers of wire-bristles made of wires of larger and smaller diameters, which increase the tightness and increase the service life of the seal.

The problem is solved due to the fact that in the method of manufacturing a brush seal of the rotor, in which supporting cheeks are placed on the sides of the mandrel, the wire is wound, then the wire winding is squeezed by the clamping cheeks, combining their outer cylindrical surfaces around the circumference of the wire winding cut, cut the wire winding, and then welded together the elements along their outer cylindrical surfaces and produce the final machining, unlike the prototype, the wire is wound with alternating layers first, a layer of wire of a larger diameter, and then, a layer of wire of a smaller diameter is wound on a formed layer of wire of a larger diameter, and a layer of wire of a smaller diameter is wound, placing a wire of a smaller diameter in the depressions formed in the layer of wire of a larger diameter between adjacent turns of wire.

In addition, additional embodiments of the method for manufacturing a brush seal are possible: a larger diameter wire is used to form the first and last layers; a metal strip is imposed on the outer cylindrical surfaces of the joined sealing elements, it is bent around the above-mentioned surfaces, the ends of the metal strip are joined by argon-arc welding into the technological ring, and the joined elements are welded by electron beam through the technological ring.

In this case, the technological ring is made of a material identical to the material of the wire having filler properties.

To implement the method, a device for manufacturing a brush rotor seal can be used, containing a mandrel in the form of rings mounted concentrically with a gap relative to each other and fastened around the circumference with screws, a device for winding and laying wire, a coil with wire, characterized in that it contains an additional a device for winding and laying wire of a smaller diameter.

The invention is illustrated by drawings. 1 shows a brush rotor seal. Figure 2 schematically shows a device for winding wire of larger and smaller diameters. Figures 1 and 2 contain: 1 - wire brush, 2 - clamping cheek, 3 - supporting cheek, 4 - stator, 5 - rotor, 6 - mandrel for winding wires, 7 - coiled layers of wire of larger and smaller diameters, 8 - coil with a wire of a larger diameter, 9 - a wire of a larger diameter, 10 - a coil with a wire of a smaller diameter, 11 - a wire of a smaller diameter.

The brush rotor seal (Fig. 1) consists of a clamping cheek 2 and a ring wire brush 1 and a supporting cheek 3 sequentially connected to it. The outer cylindrical surface of the clamping cheek 2 is made under the mounting socket in the stator 4.

Docking elements are made identical in outer diameter. A fixing pin may be installed in the supporting cheek 3 of the brush seal.

For the manufacture of brush seal rotors using a device (Fig. 2), containing a mandrel for winding wires 6, containing the outer, middle and inner rings fastened together. The device is equipped with two coils with wire: coil 8 with wire 9 (larger diameter) and coil 10 with wire 11 (smaller diameter). The device is also provided with centering clips with hubs connected by fasteners.

A method of manufacturing a brush seal of the rotors is as follows. First, the mandrel is assembled (Fig. 2). On the middle ring of the mandrel place the supporting cheeks 3 and fix them with pins. Then a layer of wire of a larger diameter 9 and a layer of wire of a smaller diameter are wound 11. Then, the wound layers of wire of a larger and smaller diameter 7 are crimped by pressing cheeks 2, combining their outer cylindrical surfaces around the circumference of the cut of wound layers of wire of a larger and smaller diameter 7. Cut the wound layers of wire of a larger and smaller diameters 7. A metal strip is applied to the outer cylindrical surfaces of the joined elements, they are bent around the aforementioned surfaces, and the ends of the metal are connected of a strip by argon arc welding into a technological ring. After that, welding of the joined elements is carried out by an electron beam through the technological ring. After welding, cut the wound layers of wire of larger and smaller diameters 7 around the circumference of the trim corresponding to the inner diameter of the brush seal, disconnect the mandrel, produce the final machining and get two brush seals (Fig. 1), ready to be placed on the stator 4.

The joint use of the group of inventions allows to increase the tightness of the brush seal and increase the service life of the rotor seal by increasing the packing density of the seal while reducing its stiffness.

Claims (7)

1. The brush seal of the rotor, made in the form of a clamping cheek and elements sequentially docked with it - an annular wire brush and a supporting cheek, characterized in that the wire brush is made of alternating rows of wires of larger and smaller diameters, and the wires of larger and smaller diameters are tightly pressed against each other to each other at the place of their fastening and are staggered relative to each other, and the rows of wires forming a brush are located in planes intersecting the axis of the rotor being sealed. 2. Brush seal according to claim 1, characterized in that the wires of a larger diameter, located in a row, are tightly pressed against each other. 3. Brush seal according to claim 1, characterized in that the wires of a smaller diameter, arranged in a row, are tightly pressed against each other. 4. Brush seal according to any one of paragraphs. 1-3, characterized in that the docked seal elements are made identical in outer diameter, and the seal is equipped with a process ring placed on the docked elements and made with a width corresponding to the total width of the said elements, and the clamping cheek is made with an end protrusion as a docking element, with this, its outer cylindrical surface is made under the installation socket. 5. A method of manufacturing a rotor brush seal, in which supporting cheeks are placed on the mandrel sides, winding the wire, then compressing the wire winding with clamping cheeks, combining their outer cylindrical surfaces around the circumference of the wire winding trimming, cutting the wire winding, and then welded the joined elements along their outer cylindrical surfaces and produce the final machining, characterized in that the wire is wound in alternating layers, at first the wire layer is larger diameter and then formed on the layer of wire wound around the larger diameter layer smaller wire diameter, the layer of wire wound around the smaller diameter, having a smaller diameter wire in the depressions formed in the larger diameter wire layer between adjacent turns of the wire. 6. The method according to p. 5, characterized in that for the formation of the first and last layers using a larger wire diameter. 7. The method according to claim 5, characterized in that a metal strip is imposed on the outer cylindrical surfaces of the docked sealing elements, bent around it on the above-mentioned surfaces, the ends of the metal strip are joined by argon-arc welding into the process ring, and the docked elements are welded by electron beam through the process ring.

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