Brush seal and method for producing the brush seal

Abstract

The invention relates to a brush seal (10) having a sealing element (16) which is formed from a multiplicity of bristles (18) and a seal head (26), wherein the seal head (26) has a core element (20) and a clamping element (24), the bristles (18) are wound around the core element (20) and are held on the core element (20) by means of the clamping element (24), the seal head (26) is provided in a cutout (30) of a housing (28), and the housing (28) has an opening portion (32) through which the bristles (18) are guided, wherein the housing (28) exerts a clamping effect on the bristles (18) in the opening portion (32) in order to minimize an exchange of material through the opening portion (32).

Description

[0001] Brush seal and method for producing the brush seal

[0002] The present invention relates to a brush seal comprising a sealing element formed from a plurality of bristles and a sealing head. The sealing head comprises a core element and a clamping element, and the bristles are wound around the core element and held to the core element by the clamping element. Furthermore, the invention relates to a bearing and a method for manufacturing the brush seal.

[0003] Typically, the sealing heads of a brush seal are housed between a support ring and a cover ring, which together form a housing for the sealing element. This enables the formation of an annular seal that can be used, for example, to axially seal a circumferential gap for an axle or shaft. The radii of the support ring and cover ring are designed according to the intended use of the brush seal. When cover rings and support rings are used, the sealing element must be deformed or bent accordingly so that it can be accommodated in the two rings. The position of the sealing element is thus fixed in relation to the two rings. The rings are usually connected in a form-fitting manner by bending or flanging a flanged lip of the support ring, with the sealing element being inserted between the support ring and cover ring. The connected rings are then inserted into the parent component to be sealed.

[0004] Brush seals are known, for example, from EP 1 146 266 A2 or EP 2 857 721 A1. Incoming gases from a turbomachine are forced to flow through the brush assembly, also known as the brush pack. The gas presses the wires against the support ring, thereby compacting the brush assembly. This minimizes the permeability of the brush seal. Due to their elasticity, the wires or fibers of the brush assembly can compensate for axial and radial rotor movements with virtually no wear and then return to their original position.

[0005] A method for producing linear or circular brush seals is disclosed, for example, in the document DE 36 06 284 A1. The method comprises winding a thread over two elongated core elements arranged parallel and spaced apart from one another to form a thread package, gripping the thread package on the two core elements at the apices, severing the thread package in a cut parallel to the core elements to produce two semi-finished brushes, and bending the semi-finished brushes into the desired brush contour.

[0006] However, brush seals have limited applications because they can be attacked by corrosive and / or aggressive gases or liquids (hereinafter referred to collectively as fluids), for example, and are therefore subject to significant wear. This has so far prevented widespread use of these seals.

[0007] The object underlying the invention is to provide a cost-effective brush seal which has a wide range of applications and which nevertheless can achieve a seal with very low leakage.

[0008] The object of the invention is achieved by a brush seal according to independent claim 1. Further advantageous embodiments are defined in the dependent claims.

[0009] The invention is based on the idea of ​​providing a brush seal in which the sealing head is housed in a housing whose interior is sealed against the fluid to be sealed. For this purpose, the housing has an opening section through which the bristles pass. This opening section is designed such that the housing exerts a clamping force on the bristles, thus sealing the sealing head against the fluid and reducing or completely preventing mass transfer with the fluid.

[0010] According to the invention, a brush seal is provided with a sealing element formed from a plurality of bristles and a sealing head, wherein the sealing head has a core element and a clamping element, the bristles are wound around the core element and are held on the core element by means of the clamping element, the sealing head is provided in a recess of a housing, and the housing has an opening section through which the bristles are passed. Here, the housing exerts a clamping effect on the bristles in the opening section to minimize mass transfer through the opening section.

[0011] In other words, the housing almost completely encloses the seal head except for the opening section through which the bristles pass. With a linear brush seal, the opening section can be suitably closed off in the longitudinal direction of the brush seal by terminating the opening section at the side, thus closing the housing. This is not necessary with an annular brush seal, in which the opening section is annular and has no end section in the tangential direction.

[0012] Unless the context explicitly or implicitly indicates otherwise, directional terms such as "axial" or "axial", "radial" or "radial", "circumferential" or "tangential" are generally to be understood as referring to an axis or shaft, the circumferential gap of which is to be sealed by the brush seal when installed.

[0013] The core element of the sealing head is, for example, a core wire, which typically has a larger cross-section than the diameter of the bristles to provide the necessary stability during production of the brush seal. The bristles, however, can be formed from thin wires or threads, for example, which can be made of a single material or a coated material.

[0014] The clamping element can, for example, be designed as a C-shaped or U-shaped clamping tube and can be made of a metal such as aluminum that can be easily deformed.

[0015] The housing has a recess designed to accommodate the sealing head. The recess is preferably only slightly larger than the sealing head to minimize the enclosed volume. If the clamping element is designed as a so-called C-tube, the recess can, in particular, be substantially circular. The recess is connected to the opening section through which the bristles of the brush seal extend.

[0016] The technology disclosed here has the advantage that the core element and the clamping element of the sealing head do not need to be resistant to the aggressive gas or fluid, as they are protected from the gas or fluid by the sealing of the opening section. Thus, the invention extends the service life of the brush seal and enables the brush seal to be used in an aggressive fluid. The invention has further advantageous embodiments that result in additional advantages.

[0017] According to a further advantageous embodiment, the brush seal is annular in order to seal a circumferential gap around a movable axis against a predetermined fluid. In other words, the brush seal can be configured to seal a circumferential gap around a movable, in particular rotatable, axis or shaft against a predetermined fluid. By means of this embodiment, for example, a plain bearing or a rolling bearing can be sealed against a predetermined fluid. These can be pivot bearings (rotational bearings) and / or linear bearings (translational bearings). Because the housing exerts a clamping effect on the bristles that are guided through the opening section, a partial or complete sealing effect of the housing against the fluid can be achieved, and the core element and the clamping element themselves can also be protected from the fluid.This makes it possible to use metals such as aluminum for the production of the brush seal, which are not resistant to the fluid.

[0018] According to a further advantageous embodiment, the housing is formed in one piece. In particular, the housing can be formed from a profiled sheet metal, as a cast part, or as an additively manufactured part, for example, by means of selective laser melting. Furthermore, the housing can be manufactured by a bending process. This enables cost-effective production of the housing. Furthermore, it can ensure that suitable housings can be designed for a wide variety of requirements, such as a variety of installation situations or a variety of components to be sealed.

[0019] According to a further advantageous embodiment, the housing is formed in two parts from a support body and a cover body, wherein the cover body is held in a form-fitting manner by the support body in order to form the recess with the opening section. This means that the housing can be produced from at least two parts. For example, it is conceivable for the housing to be formed from two halves, such as a support ring and a cover ring. The parts of the housing can be connected to one another in a material-fitting and / or form-fitting manner. For example, the support ring and the cover ring can be welded to one another or can be connected to one another in a form-fitting manner by means of a flanged lip that is bent or flanged over. In this case, the opening section is the only opening of the housing towards the exterior of the housing, so that the sealing head is almost completely enclosed by the housing.This means that the sealing head is specially protected from the fluid, gas or liquid in a usage situation.

[0020] According to a further advantageous embodiment, a material of the bristles is selected depending on a liquid medium such that a surface tension of the bristle material compared to the liquid medium reduces, in particular prevents, wetting of the bristles. In this case, the fluid is a liquid. In other words, the material of the bristles can be selected such that a surface tension reduces or prevents wetting of the bristles. This also leads to improved tightness of the brush seal, since the surface tension of the bristles compared to the liquid causes individual bristles to be pressed against the brush body by the liquid, allowing the bristles to seal the opening gap better. Furthermore, a high surface tension of the bristle material compared to the liquid prevents the bristles from becoming saturated, and the liquid can pass through the opening section.This design thus achieves a particularly preferred sealing of the sealing head in the housing.

[0021] According to a further advantageous embodiment, the bristles are made of a superalloy, in particular Haynes 25. Alternatively, the bristles can be made of ceramic fibers, for example. Haynes 25 is defined, for example, in the MTU standard MTS1288-1. The chemical composition of Haynes 25 is given below in Table 1.

[0022] Table 1. The Haynes 25 alloy withstands high temperatures and oxidizing atmospheres up to 980 °C and is also resistant to sulfides. Advantageously, Haynes 25 also exhibits a high surface tension, so a brush seal with bristles made of a superalloy such as Haynes 25 enables a particularly advantageous design of the brush seal of the presently disclosed technology.

[0023] According to a further aspect of the invention, a bearing with a brush seal according to the technology described above for sealing a plain bearing or a rolling bearing is provided. These can be rotary bearings and / or linear bearings.

[0024] Finally, the invention also relates to a method for producing a brush seal, comprising the steps of providing a substantially straight sealing element which is formed from a plurality of bristles, with a sealing head which has a core element and a clamping element, wherein the bristles are wound around the core element and are held on the core element by means of the clamping element, forming, in particular bending, the sealing element with core element and clamping element so that the sealing element has a shape which is at least approximately suitable for installation in a component to be sealed, in particular substantially a semicircular shape or circular shape, and forming the housing with an opening section, wherein the sealing head is provided in a recess of the housing and the bristles are guided through the opening section.

[0025] The invention is described below by way of example and not by way of limitation with reference to the accompanying figures. Further features of the invention will become apparent from the claims, the figures, and the description of the figures.

[0026] Fig. 1 shows a schematic and simplified sectional view of a brush seal with a housing in an installed state in a component to be sealed; and

[0027] Fig. 2 shows a schematic and simplified sectional view of a brush seal according to a further embodiment.

[0028] Fig. 1 shows a schematic and simplified sectional view of a brush seal 10, wherein the brush seal 10 can be used to seal a gap 50 between a first part 12 of a component to be sealed and a second part 14 of the component to be sealed. According to Fig. 1, for example, a bearing (not shown) can be located on the left side of the brush seal 10, wherein in the use situation a fluid 42 can be located on the right side of the brush seal 10. The brush seal 10 has a sealing element 16 which is formed from a plurality of bristles 18, wherein the bristles 18 are held in a sealing head 26. The sealing head 26 comprises a core element 20 around which the bristles 18 are wound and the bristles 18 are held on the core element 20 by means of the clamping element 24. In this case, the core element 20 can be a core wire, for example. The clamping element 24 can, for example, be a C-shaped clamping tube.The bristles 18 can be made from a solid material or can be made from a coated material. The sealing head 26 is located in a recess 30 of a housing 28. The housing 28 is attached to the part 14 in such a way that the gap 50 on the left side of the brush seal 10 in Fig. 1 between the first part 12 and the second part 14 of the component to be sealed can be completely sealed. The housing has an opening section 32 through which the bristles 18 are passed. This means that the housing 28 almost completely encloses the sealing head 26, and the housing 28 is designed such that it exerts a clamping effect on the bristles 18 in the opening section 32 in order to minimize, reduce, and in particular prevent an exchange of the fluid 42 through the opening section 32.The bristles 18 are dimensioned in length such that the free ends 22 of the bristles 18 rest on the first part 12 of the component to be sealed. Because the bristles 18 are elastic, they can compensate for radial movement of the first part 12 to a certain extent. Thus, the brush seal 10 can prevent or reduce the penetration of the fluid 42 into the gap 50 between the first part 12 and the second part 14, and at the same time, the brush seal 10 prevents the fluid 42 from penetrating the recess 30 within the housing 28. This makes it possible to form the core element 20 and the clamping element 24 of the sealing head 26 from a material that would otherwise be unstable to the liquid or fluid 42. This enables a broad application of the brush seal 10 according to the invention.

[0029] In the case of an annular brush seal 10, the brush seal 10 can be designed to seal a circumferential gap, such as the gap 50, around a movable axis against a predetermined fluid 42. This can be used, for example, to seal a bearing (not shown), which can be located, for example, on a left side of the brush seal 10 in Fig. 1, against the fluid 42, which can contain particles, dust, or aggressive substances.

[0030] A material of the bristles 18 can be selected depending on the fluid 42 such that a surface tension of the bristle material relative to the fluid 42 reduces, in particular prevents, wetting of the bristles 18. In this case, the fluid 42 is a liquid. This enables better sealing of the bearing, prevents the bristles 18 from becoming saturated with the fluid 42, and enables better sealing of the gap 50 relative to the fluid 42. Furthermore, a surface tension that reduces wetting of the bristles 18 prevents the fluid 42 from passing through the opening section 32. Thus, a mass transfer between the fluid 42 and the recess 30 is reduced or prevented.

[0031] Fig. 2 shows a schematic view of a brush seal 10 according to a further advantageous embodiment. Here, a similar arrangement is shown as previously in Fig. 1, wherein, however, the housing 28 is formed from a support ring or support body 44 and a cover ring or cover body 46. The cover body 46 is held in a form-fitting manner by the support body 44 in that the flanged lip 48 is bent radially inward. The flanged lip 48 can also be used to easily exert a clamping effect on the opening section 32. As before, the opening section 32 is designed such that mass transfer from the fluid 42 into the recess 30 in the housing 28 is reduced. The support body 44 has a projection at its lower end, i.e. radially inward, which supports the bristles 18 in the axial direction relative to the gap 50.Such a brush seal is particularly advantageous when the fluid 42 is subjected to high pressure relative to the gap 50 between part 12 and part 14 of the component to be sealed, and can achieve a good sealing effect. This means that the housing 28 is formed in two parts, consisting of a support body 44 and a cover body 46, with the cover body 46 being held in place by the support body 44. As before, the opening section 32 is the only opening of the housing 28 to the exterior of the housing 28 or to the fluid 42.

[0032] By means of this embodiment, for example, the core element 20 and / or the clamping element 24 can be formed from a material that is not resistant to the fluid 42 in a use position. In particular, the clamping element 24 can be formed from aluminum, for example, since the clamping element 24 is protected from the fluid by the sealing effect of the opening section 32. In a particularly advantageous embodiment, the material of the bristles 18 is selected depending on the fluid 42 such that a surface tension of the bristle material with respect to the fluid 42 reduces, in particular prevents, wetting of the bristles 18. The fluid 42 can be a liquid. This can ensure that the bristles 18 do not absorb the fluid 42 or that the fluid 42 cannot pass through the opening section 32 or at least a

[0033] Mass transfer between the recess 30 and the fluid 42 is reduced. This leads to a longer service life of the brush seal 10 in an aggressive fluid 42 that is capable of attacking the sealing head of the brush seal 10, in particular corroding and / or dissolving it. In particular, the bristles 18 can be formed from a superalloy, and in particular from Haynes 25.

[0034] List of reference symbols:

[0035] 10 brush seal

[0036] 12 Part of the component to be sealed

[0037] 14 Part of the component to be sealed

[0038] 16 Sealing element

[0039] 18 bristles

[0040] 20 core element

[0041] 22 free ends

[0042] 24 clamping element

[0043] 26 Sealing head

[0044] 28 housings

[0045] 30 recess

[0046] 32 opening section

[0047] 42 Fluid

[0048] 44 support bodies

[0049] 46 cover bodies

[0050] 48 flanged lip

[0051] 50 gap

Claims

Patent claims 1. Brush seal (10) with a sealing element (16) consisting of a plurality of bristles (18) and a sealing head (26), wherein - the sealing head (26) has a core element (20) and a clamping element (24), - the bristles (18) are wound around the core element (20) and are held on the core element (20) by means of the clamping element (24), - the sealing head (26) is provided in a recess (30) of a housing (28), and - the housing (28) has an opening section (32) through which the bristles (18) are guided, characterized in that the housing (28) of the brush seal (10) exerts a clamping effect on the bristles (18) in the opening section (32) to minimize mass transfer through the opening section (32).

2. Brush seal (10) according to claim 1, wherein the brush seal (10) is annular in shape to seal a circumferential gap (50) about a movable axis against a predetermined fluid (42).

3. Brush seal (10) according to one of the preceding claims, wherein the housing (28) is formed in one piece.

4. Brush seal (10) according to one of the preceding claims, wherein the housing (28) is formed in two parts from a support body (44) and a cover body (46).

5. Brush seal (10) according to claim 4, wherein the cover body (46) is held in a form-fitting manner by the support body (44) in order to form the recess (30) with the opening section (32), the opening section (32) forming the only opening of the housing (28) towards an exterior of the housing (28).

6. Brush seal (10) according to claim 4 or 5, wherein the support body (44) and the cover body (46) each form a leg which, viewed in a cross-section, extends at least in sections substantially parallel to the bristles, wherein the legs of the housing (28) define the opening (28) relative to an exterior of the housing (28).

7. Brush seal (10) according to claim 6, wherein the support body (44) and / or the cover body (46) has a clamping rib extending parallel to the core element, which exerts the clamping effect on the bristles (18) in the opening section (32) to minimize mass transfer through the opening section (32).

8. Brush seal (10) according to one of claims 4 to 7, wherein the support body (44) is designed such that, viewed in a cross-section, it extends in a leg-like manner at least in sections substantially parallel to the bristles (18), and along its longitudinal extent contacts the bristles (18) in a clamping manner at a first contact point closer to the core and contacts the bristles in a supporting manner at a second contact point further away from the core, in particular the cover body (46) contacts the bristles (18) only at the level of the contact point closer to the core in order to contribute to the clamping effect on the bristles.

9. Brush seal (10) according to one of the preceding claims, wherein a material of the bristles (18) is selected depending on a fluid (42) such that a surface tension of the bristle material with respect to the fluid (42) reduces, in particular prevents, wetting of the bristles (18).

10. Brush seal according to one of the preceding claims, wherein the bristles are formed from a superalloy, in particular from Haynes 25.

11. A method for producing a brush seal, comprising the steps: Providing a substantially straight sealing element formed from a plurality of bristles, with a sealing head having a core element and a clamping element, wherein the bristles are wound around the core element and are held on the core element by means of the clamping element, Forming, in particular bending, the sealing element with core element and clamping element, so that the sealing element has a shape that is at least approximately suitable for installation in a component to be sealed, in particular essentially a semicircular shape or a circular shape, and - forming the housing with an opening section, wherein the sealing head (26) is provided in a recess (30) of the housing (28) and the bristles (18) are passed through the opening section (32).

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